List of Numbers episodes

Numb3rs /ˈnʌmbərz/ is an American television series produced by brothers Ridley and Tony Scott. It premiered on CBS on Sunday, January 23, 2005 at 10:00 pm with its pilot episode then moved to its Friday slot five days later. It remained in that slot for the rest of its run. The series is set in Los Angeles, California, and follows the stories of an Federal Bureau of Investigation (FBI) team and a mathematics professor, focusing on relationships between FBI Special Agent in Charge Don Eppes (Rob Morrow), his brother Professor Charlie Eppes (David Krumholtz) and their father, Alan Eppes (Judd Hirsch), and on the brothers' efforts to fight crime. A typical episode begins with a crime, which is subsequently investigated by Don's team and mathematically described by Charlie. The insights provided by Charlie's mathematics are almost always crucial to solving the crime.

In total, six complete seasons consisting of 118 episodes were broadcast. The first season, a mid-season replacement for Dr. Vegas, was the shortest of the six, and spanned 13 episodes from January to May 2005. Seasons two and three aired from September to May of the 2005–2006 and 2006–2007 seasons respectively, but season four was cut short by the 2007–2008 Writers Guild of America strike. Twelve episodes were originally produced and aired from September 2007 to January 2008. Six more episodes were aired in April and May 2008 after the strike ended. Season 5 began airing on October 3, 2008 and continued through to May 2009. Season six began in late September 2009 and concluded in March 2010.

In addition to being broadcast on television, Numb3rs is available on DVD. All seasons have been released encoded for Region 1, and seasons one, two, three, four, and five have been released encoded for Regions 2 and 4. Individual episodes of Numb3rs can also be purchased by registered members of the US iTunes Store and as video on demand from NetFlix and Amazon Unbox. CBS also streams recently broadcast episodes on its website.

Series overview

Season		Episodes	Originally aired		DVD release
			Season premiere	Season finale	Region 1	Region 2	Region 4
	1	13	January 23, 2005 (2005-01-23)	May 13, 2005 (2005-05-13)	May 30, 2006 (2006-05-30)	October 2, 2006 (2006-10-02)	October 5, 2006 (2006-10-05)
	2	24	September 23, 2005 (2005-09-23)	May 19, 2006 (2006-05-19)	October 10, 2006 (2006-10-10)	July 9, 2007 (2007-07-09)	July 7, 2007 (2007-07-07)
	3	24	September 22, 2006 (2006-09-22)	May 18, 2007 (2007-05-18)	September 25, 2007 (2007-09-25)	February 9, 2009 (2009-02-09)	July 10, 2008 (2008-07-10)
	4	18	September 28, 2007 (2007-09-28)	May 16, 2008 (2008-05-16)	September 30, 2008 (2008-09-30)	July 13, 2009 (2009-07-13)	July 13, 2009 (2009-07-13)
	5	23	October 3, 2008 (2008-10-03)	May 15, 2009 (2009-05-15)	October 20, 2009 (2009-10-20)	June 21, 2010 (2010-06-21)	August 5, 2010 (2010-08-05)
	6	16	September 25, 2009 (2009-09-25)	March 12, 2010 (2010-03-12)	August 10, 2010 (2010-08-10)	July 18, 2011 (2011-07-18)	July 21, 2011 (2011-07-21)

Episode list

Season 1 (2005)

For a more comprehensive list, see List of Numb3rs episodes (season 1).

No.	#	Title	Directed by	Written by	U.S. viewers (million)	Original air date	Production code
1	1	"Pilot"	Davis Guggenheim & Mick Jackson	Nicolas Falacci & Cheryl Heuton	24.92	January 23, 2005 (2005-01-23)	101
Charlie assists Don on a serial rapist case by calculating a "hot zone", an area where the rapist is most likely to live. Don is removed from the case after Charlie's formula fails to turn up any leads. A comment from their father then leads Charlie to change the equation to calculate two points of origin, instead of one. First appearance of: Don Epps, Charlie "Charles" Epps, Alan Epps, David Sinclair, Terry Lake, Amita Ramanujan and Larry Fleinhardt. Mathematics used: Geographic profiling, probability theory, 11-dimensional supergravity theory and projectile motion
2	2	"Uncertainty Principle"	David Von Ancken	Nicolas Falacci & Cheryl Heuton	15.46	January 28, 2005 (2005-01-28)	104
Charlie successfully predicts the time and place of a bank robbery using what he says are elements of Heisenberg's uncertainty principle, but when the planned arrest goes bad, he retreats into the math problem P vs. NP. Mathematics used: P vs. NP and Heisenberg's uncertainty principle
3	3	"Vector"	David Von Ancken	Jeff Vlaming	11.55	February 4, 2005 (2005-02-04)	103
A deadly strain of influenza is spreading through Los Angeles. Don investigates whether the strain was released deliberately, and Charlie tries to calculate the origin and likely spread of the virus. Mathematics used: Patient Zero, Viral vector, Vector and SIR model
4	4	"Structural Corruption"	Tim Matheson	Liz Friedman	10.68	February 11, 2005 (2005-02-11)	105
An engineering student commits suicide, but Charlie suspects foul play. Don disagrees, but he agrees to help Charlie investigate whether the student was murdered because of his research into a building's structural integrity. Mathematics used: Pendulum and Foucault pendulum
5	5	"Prime Suspect"	Lesli Linka Glatter	Doris Egan	10.49	February 18, 2005 (2005-02-18)	106
A young girl is kidnapped, but her parents refuse to cooperate with Don's investigation. The girl's father is a mathematician, and the kidnapping may be related to his work on the Riemann hypothesis. Mathematics used: Cryptography, prime numbers, Riemann hypothesis and Riemann zeta function
6	6	"Sabotage"	Lou Antonio	Liz Friedman	11.46	February 25, 2005 (2005-02-25)	102
Don is investigating a series of train accidents which are recreations of previous wrecks. The saboteur leaves a note composed entirely of numbers. Mathematics used: Kasiski examination, Cryptography, Fibonacci sequence, golden ratio and Beale ciphers
7	7	"Counterfeit Reality"	Alex Zakrzewski	Andrew Dettman	10.55	March 11, 2005 (2005-03-11)	107
A strange series of robberies leads Don into a case involving counterfeit money, kidnapping and murder. Don is aided by Secret Service agent Kim Hall while Charlie uses math to analyze fake bank notes and track their spread. Mathematics used: Guilloché pattern and wavelet analysis
8	8	"Identity Crisis"	Martha Mitchell	Wendy West	9.99	April 1, 2005 (2005-04-01)	108
A new case with disturbing similarities to an old case leads Don to question whether he put the right man in jail. While Don tries to find the connection between the two cases, he asks Charlie to look for mistakes or flaws in the first case. Mathematics used: Poker, geometric progression - paper folding, pyramid scheme, fingerprint and Schrödinger's cat
9	9	"Sniper Zero"	J. Miller Tobin	Ken Sanzel	10.54	April 15, 2005 (2005-04-15)	109
Don is investigating a series of sniper killings, and Charlie is searching for an underlying pattern to the attacks. What appears to be bad data can't be eliminated from the analysis, because it fits the only pattern he can find. Features appearance by Lou Diamond Phillips as Ian Edgerton. Mathematics used: Projectile motion, Tipping point, regression toward the mean and exponential growth
10	10	"Dirty Bomb"	Paris Barclay	Andrew Dettman	11.50	April 22, 2005 (2005-04-22)	110
A truck carrying radioactive waste disappears, and Don fears that a dirty bomb will be set off in downtown Los Angeles. When three suspects are caught, Charlie must try to convince one of them to give up the others and give the location of the waste. Mathematics used: Prisoner's dilemma and radioactive decay
11	11	"Sacrifice"	Paul Holahan	Ken Sanzel	10.80	April 29, 2005 (2005-04-29)	111
A researcher is murdered in his home, and Charlie must reconstruct data erased from his computer while Don investigates possible suspects. Mathematics used: Sabermetrics and econometrics Final appearance of: Terry Lake.
12	12	"Noisy Edge"	J. Miller Tobin	Nicolas Falacci & Cheryl Heuton	11.80	May 6, 2005 (2005-05-06)	112
An unidentified flying object travels over Los Angeles and then disappears. Don suspects terrorist activity, and Charlie tries to find out more about the object and its flight path. Mathematics used: Combinatorics and conditional probability distribution - "squish-squash" with Fourier analysis
13	13	"Man Hunt"	Martha Mitchell	Andrew Dettman	11.29	May 13, 2005 (2005-05-13)	113
A prison bus crashes, allowing two dangerous convicts to escape. Don is joined by his former partner from Fugitive Recovery as the Bureau launches an effort to recapture them Mathematics used: Bayesian inference, Markov chain, Chapman–Kolmogorov equation and Monty Hall problem

Season 2 (2005–2006)

For a more comprehensive list, see List of Numb3rs episodes (season 2).

No.	#	Title	Directed by	Written by	U.S. viewers (million)	Original air date	Production code
14	1	"Judgment Call"	Alex Zakrzewski	Ken Sanzel	11.18	September 23, 2005 (2005-09-23)	201
When a judge's wife is shot and killed, Don and his team look into the judge's cases to determine if one of his verdicts led to the murder. Mathematics used: Scatterplot, Bayesian Spam Filtering, Buffon's needle and Conditional Probability First appearances of: Colby Granger and Megan Reeves.
15	2	"Better or Worse"	J. Miller Tobin	Andrew Dettman	11.83	September 30, 2005 (2005-09-30)	202
Don and his team are called in when a woman attempting to rob a jewelry store in Beverly Hills is shot by a security guard. Mathematics used: Von Neumann cellular automata, Farey sequence and pseudo-random numbers
16	3	"Obsession"	John Behring	Robert Port	11.40	October 7, 2005 (2005-10-07)	203
The FBI becomes involved in the stalking of a popular singer after she is threatened by an intruder in her house and reveals a series of threatening letters she has received through the mail. Mathematics used: Trigonometry, curvelet analysis, Forensic Information System for Handwriting (FISH), spherical astronomy and art gallery problem
17	4	"Calculated Risk"	Bill Eagles	J. David Harden	11.09	October 14, 2005 (2005-10-14)	204
Don and Megan are called to the murder scene when the CFO of a powerful energy company—who was about to testify against her fellow executives—is murdered at her home and her son is the only witness. Mathematics used: Conditional probability and compound interest
18	5	"Assassin"	Bobby Roth	Nicolas Falacci & Cheryl Heuton	11.17	October 21, 2005 (2005-10-21)	205
Along with David Sinclair and new FBI Agent Colby Granger, Don discovers a secret code during a raid and enlists Charlie's help to crack it. Mathematics used: Transposition cipher, game theory and paper planes
19	6	"Soft Target"	Andy Wolk	Don McGill	11.13	November 4, 2005 (2005-11-04)	206
A week-long series of counter-terrorism exercises are put to the test by Homeland Security in Los Angeles, but the first one is violated by someone who releases a potentially lethal gas in the subway system. Mathematics used: Percolation theory and diffusion
20	7	"Convergence"	Dennis Smith	Nicolas Falacci & Cheryl Heuton	12.36	November 11, 2005 (2005-11-11)	207
Don investigates a series of home invasions in which the thieves steal only high-end items from wealthy individuals. Meanwhile, an old adversary challenges Charlie's work. Mathematics used: Group theory, data-mining, Fourier analysis, calendars, Three-dimensional trilateration, Set theory and projectile motion
21	8	"In Plain Sight"	John Behring	Julie Hébert	12.44	November 18, 2005 (2005-11-18)	208
Megan feels responsible for an agent's death following an explosion at a house where meth is being illegally produced and that the FBI targeted for a bust but the case takes a new direction after Charlie discovers that the drug kingpin was in the FBI office, looking for help in rescuing his supposedly kidnapped daughter. Mathematics used: Flock behavior, steganography and matrices - error correction code
22	9	"Toxin"	Jefery Levy	Ken Sanzel	12.67	November 25, 2005 (2005-11-25)	209
Don learns that someone is poisoning non-prescription drugs made by a leading pharmaceutical company after four people nearly die from the tampering. Mathematics used: Information theory - information entropy, graph theory - Seven Bridges of Königsberg and soap bubble theory with Steiner tree
23	10	"Bones of Contention"	Jeannot Szwarc	Christos Gage & Ruth Fletcher	12.53	December 9, 2005 (2005-12-09)	210
An archaeologist is killed in a museum, and the object she was studying is taken. Mathematics used: Exponential decay and Voronoi diagram
24	11	"Scorched"	Norberto Barba	Sean Crouch	11.96	December 16, 2005 (2005-12-16)	211
An arsonist believed to be part of an extremist environmental group sets a fire at a car dealership that kills a salesman. The group's name is spray painted at the scene and is the fourth such fire, but the first to claim a life. Mathematics used: Combustion and principal components analysis
25	12	"The OG"	Rod Holcomb	Andrew Dettman	13.93	January 6, 2006 (2006-01-06)	212
When Don and his team are called to the murder scene of a Los Angeles gang member, they learn the victim is a fellow agent who had been working undercover. Mathematics used: Poisson distribution and social network analysis
26	13	"Double Down"	Alex Zakrzewski	Don McGill	12.98	January 13, 2006 (2006-01-13)	213
When the FBI is called to investigate a murder at a Los Angeles card club, it leads the agents to unravel a complicated card counting scheme involving a group of college students whose lives may now be at risk. Mathematics used: Probability involving sampling without replacement, time series analysis and randomization
27	14	"Harvest"	John Behring	J. David Harden	13.22	January 27, 2006 (2006-01-27)	214
A South Asian teenager is found in the blood-spattered basement of an old downtown hotel where she was apparently being tortured. The investigation soon reveals that the girl, along with three other missing women, are victims of a black-market organ-harvesting scheme. Mathematics used: Markov chain, ellipses and genetic variation
28	15	"The Running Man"	Terrence O'Hara	Ken Sanzel	13.31	February 3, 2006 (2006-02-03)	215
A DNA synthesizer with the capability of customizing diseases is stolen from the campus where Charlie teaches, and Don fears the thieves may be terrorists out to start or advance a bio-warfare program. Mathematics used: Benford's law, continued fraction, astronomy, and probability
29	16	"Protest"	Dennis Smith	Nicolas Falacci & Cheryl Heuton	11.94	March 3, 2006 (2006-03-03)	216
A pedestrian is killed when a homemade bomb explodes under a car outside of a downtown Army recruiting center. The investigation reveals that a similar bombing occurred exactly 35 years ago at an ROTC office that killed two people. Things take a turn when Don discovers that his father was a member of an anti-war group believed to have been associated with the bombings. Mathematics used: Graph theory, Ramsey numbers and recursive sequence
30	17	"Mind Games"	Peter Markle	Andrew Dettman	11.67	March 10, 2006 (2006-03-10)	217
When the bodies of three illegal-immigrant women are found on government-owned land in a wilderness area, Don investigates and learns a psychic led the police to the crime scene after allegedly seeing visions of the bodies. Charlie becomes extremely annoyed after learning that Don is using the psychic's help to solve the case, maintaining that true psychics do not exist. Mathematics used: Fokker-Planck equation and Binomial theorem
31	18	"All's Fair"	Rob Morrow	Julie Hébert	12.09	March 31, 2006 (2006-03-31)	218
In an effort to find the murderer of an Iraqi woman, Don enlists the help of the victim's cousin, who lives in Los Angeles. Through her cousin, Don learns information about the woman's disturbing connection to Saddam Hussein, which could lead to her murderer. Meanwhile, Charlie reunites with an ex-girlfriend, a best-seller neuropsychologist. Mathematics used: Density, Sudoku, logistic regression and game theory
32	19	"Dark Matter"	Peter Ellis	Don McGill	13.69	April 7, 2006 (2006-04-07)	219
As Don and his team investigate the motive behind two students's deadly school shooting, Charlie uses the school's radio frequency identification system to track the shooters's movements through the school's hallways. But the team are stunned when Charlie reveals that they're looking for a third shooter, someone with motive. Mathematics used: RFID and optimization problem
33	20	"Guns and Roses"	Stephen Gyllenhaal	Robert Port	12.09	April 21, 2006 (2006-04-21)	220
When an ATF agent is found dead amid questionable circumstances, Don demands to take on the case, which revolves around an elaborate bank heist, after he learns the victim is his ex-girlfriend. Mathematics used: Echolocation and biomathematics (DNA sequence alignment)
34	21	"Rampage"	J. Miller Tobin	Ken Sanzel	12.32	April 28, 2006 (2006-04-28)	221
After an unknown man opens fire in the FBI offices, causing carnage and destruction, Don and his team must investigate his motive and his connection to a dangerous arms dealer who is on trial. Meanwhile, Don soon learns that the bullet that killed the sex offender the team interviewed came from Colby's gun, forcing Colby to be put on desk duty for the time being. Mathematics used: Chaos theory, Brownian Motion, Self-organized criticality, Venn diagram and tesseracts/hypercubes
35	22	"Backscatter"	Bill Eagles	Nicolas Falacci & Cheryl Heuton	12.01	May 5, 2006 (2006-05-05)	222
An FBI investigation into a computer hacking scam, which taps into a bank's system to gain access to customer's identities and financial assets, becomes personal for Don when the Russian mob spearheading it comes after him and threatens the safety of Charlie and Alan. Mathematics used: Explicit and implicit functions, geometric progression and exponential growth. Neil Sloane's Integer Sequence Database was also used.
36	23	"Undercurrents"	J. Miller Tobin	J. David Harden	12.35	May 12, 2006 (2006-05-12)	223
Five young Chinese girls wash up on the shore; while Charlie works out where they came from, it emerges that one of the girls is carrying Avian Flu. Mathematics used: Encoding, vector fields, kinematics, n-dimensional space and strange loop.
37	24	"Hot Shot"	John Behring	Barry Schindel	12.72	May 19, 2006 (2006-05-19)	224
When two women are found dead with an apparent drug overdose, Don suspects a serial killer. Charlie's help on Don's case is hindered by his bizarre dream about his mother. Mathematics used: Directed graph, parabolic equations, probability and trajectory

Season 3 (2006–2007)

For a more comprehensive list, see List of Numb3rs episodes (season 3).

No.	#	Title	Directed by	Written by	U.S. viewers (million)	Original air date	Production code
38	1	"Spree (Part 1)"	John Behring	Ken Sanzel	11.35	September 22, 2006 (2006-09-22)	301
Don is on the trail of a criminal couple consisting of a 30 year old teacher and a 17 year student who are committing crimes across the country. Charlie and Amita's relationship changes and Alan decides to move out. The episode ends in a cliffhanger with Crystal Hoyle, the 30-year-old teacher, taking Megan hostage. Mathematics used: Pursuit curves and geodesic sphere
39	2	"Two Daughters (Part 2)"	Alex Zakrzewski	Ken Sanzel	10.69	September 29, 2006 (2006-09-29)	302
A continuation of "Spree" Mathematics used: Polar spirals and parametric equations
40	3	"Provenance"	David Von Ancken	Don McGill	11.07	October 6, 2006 (2006-10-06)	303
A famous Nazi-looted painting is stolen from a museum and a related murder surfaces. Mathematics used: Linear diophantine equations, curvelet analysis, Craquelure and discriminant analysis
41	4	"The Mole"	Stephen Gyllenhaal	Robert Port	10.89	October 13, 2006 (2006-10-13)	304
The death of a Chinese interpreter leads Don and his team to investigate a possible mole from within the Department of Justice. Colby covers up information on Don's case for a friend (Shawn Hatosy). Charlie is upset when Larry publishes a paper without his help. Mathematics used: Steady Motion Algorithm, Curtate cycloid, symmetry and combinatorics
42	5	"Traffic"	J. Miller Tobin	Nicolas Falacci & Cheryl Heuton	11.95	October 20, 2006 (2006-10-20)	305
A series of violent highway attacks which appear to be random puzzles Don and his team. Mathematics used: Randomness, partial differential equations and traffic flow
43	6	"Longshot"	John Behring	J. David Harden	11.09	October 27, 2006 (2006-10-27)	306
The team investigates the death of a man armed with a sophisticated statistical analysis that can identify the winning horse at a race track. Mathematics used: Probability, arbitrage betting and data mining
44	7	"Blackout"	Scott Lautanen	Andrew Dettman	11.08	November 3, 2006 (2006-11-03)	307
After an attack on a power station which left parts of Los Angeles in the dark, the team must find the assailant's real target. Mathematics used: Set Theory, Center of mass, harmonic series, directed graph, Load flow analysis and Dantzig-Wolfe Decomposition
45	8	"Hardball"	Fred Keller	Nicolas Falacci & Cheryl Heuton	11.76	November 10, 2006 (2006-11-10)	308
A minor league baseball player is found dead of steroid abuse, leading the investigators to an unusual chain of suspects. Mathematics used: Sabermetrics and Shiryaev-Roberts change-point analysis
46	9	"Waste Not"	J. Miller Tobin	Julie Hébert	10.73	November 17, 2006 (2006-11-17)	309
Mysterious cancer clusters are found around a number of elementary schools whose playgrounds were all paved by the same company. A new CalSci administrator annoys Charlie and his colleagues, while Alan dates her. Mathematics used: Groundwater flow equation, cancer clusters, seismic tomography and Kac–Moody algebra
47	10	"Brutus"	Oz Scott	Ken Sanzel	11.73	November 24, 2006 (2006-11-24)	310
A California State Senator and a psychiatrist—neither have much in common with the other except for one thing...they both turn up dead on Don's watch. While the circumstances of their deaths are different, Don thinks the two murders are related, and tries to prove his hunch right. What he finds may bring to light a deep secret the government has been hiding for years. Mathematics used: Network flow, network theory, Euclid's Orchard and target selection theory
48	11	"Killer Chat"	Chris Hartwill	Don McGill	11.23	December 15, 2006 (2006-12-15)	311
Don and Charlie track a killer who has murdered several sex predators. The predators took advantage of teenage girls they met in chat rooms. Meanwhile, Larry is ready to begin an adventure with NASA. Mathematics used: Statistical Textual Analysis and principal components analysis
49	12	"Nine Wives"	Julie Hébert	Julie Hébert	12.35	January 5, 2007 (2007-01-05)	312
Don, Charlie, and the team search for a polygamist who is on the FBI's Ten Most Wanted List for rape and murder. Mathematics used: Lévy flights, Inbreeding coefficients and kinship chains
50	13	"Finders Keepers"	Colin Bucksey	Andrew Dettman	11.58	January 12, 2007 (2007-01-12)	313
After an extremely expensive yacht sinks in the middle of a race, Charlie is put between a rock and a hard place when Don and the NSA need his help on the case. Mathematics used: Fluid dynamics, constraint and optimization
51	14	"Take Out"	Leslie Libman	Sean Crouch	10.91	February 2, 2007 (2007-02-02)	314
When two police officers are killed while eating dinner out, Charlie tries to figure out where the killers will strike next. Don's superiors make him see the department shrink. Mathematics used: Outliers and data mining
52	15	"End of Watch"	Michael Watkins	Robert Port & Mark Llewellyn	11.23	February 9, 2007 (2007-02-09)	315
Don and the team reopen a cold case when an LAPD badge turns up at a construction site. When Charlie joins the investigation, they attempt to track down the owner of the badge, an officer who has been missing 17 years. Meanwhile, Alan is informed that he's being sued. Mathematics used: Laser Swath Mapping and quantum mechanics
53	16	"Contenders"	Alex Zakrzewski	J. David Harden	10.69	February 16, 2007 (2007-02-16)	316
One of David's closest friends is called into question after a man dies during an Mixed martial arts sparring match. When it turns out this is not the first time such an event has happened, things look even worse. Charlie is busy practicing what little he knows about poker, so he can take Larry's spot in a tournament. Mathematics used: Kruskal's algorithm and Flow network
54	17	"One Hour"	J. Miller Tobin	Ken Sanzel	11.02	February 23, 2007 (2007-02-23)	317
Don talks to his therapist again, and while he's gone, the team races to find an eleven year-old boy being held on a $3 million ransom. Mathematics used: 'Cake-cutting' algorithm, logic maze and state diagram
55	18	"Democracy"	Steve Boyum	Nicolas Falacci & Cheryl Heuton	10.29	March 9, 2007 (2007-03-09)	318
Several area murders seem to be tied to voter fraud. Don, Charlie, and the team must find the killers before they strike again. Mathematics used: Statistics, probability theory, metadata and organizational theory
56	19	"Pandora's Box"	Dennis Smith	Andrew Black	10.74	March 30, 2007 (2007-03-30)	319
When a jet crashes in the middle of a forest, Charlie suspects that there is more to the crash than meets the eye. Mathematics used: Ito-Stratonovich drift integrals and wavelet deconvolution
57	20	"Burn Rate"	Frederick K. Keller	Don McGill	10.93	April 6, 2007 (2007-04-06)	320
Don and Charlie hunt for a serial letter bomber and disagree over whether a key suspect, a physics professor working as a consultant on explosives for the Department of Defense who eluded conviction once before, is responsible for the latest murder. Mathematics used: Explosions, paradigm shift, coherence and outliers
58	21	"The Art of Reckoning"	John Behring	Juile Hébert	10.15	April 27, 2007 (2007-04-27)	321
When a former mob hit man on death row suddenly has a change of heart and agrees to confess to his crimes, Don has an uneasy feeling about the whole affair. Larry returns from his NASA mission. Mathematics used: Probability theory and tit for tat
59	22	"Under Pressure"	J. Miller Tobin	Andrew Dettman	9.51	May 4, 2007 (2007-05-04)	322
Don, Charlie and the team take on unknown terrorists who may be using nerve gas to undermine the city's water supply. Mathematics used: Social network analysis
60	23	"Money For Nothing"	Stephen Gyllenhaal	Nicolas Falacci & Cheryl Heuton	10.03	May 11, 2007 (2007-05-11)	323
$50 million dollars in medical relief is stolen. Someone other than the FBI wants to recover the shipment. Don and the team find themselves pitted against blackmarketeers in a race for the supplies. Mathematics used: Greedy algorithm and Dijkstra's algorithm
61	24	"The Janus List"	John Behring	Robert Port & Ken Sanzel	10.18	May 18, 2007 (2007-05-18)	324
In the wake of a deadly standoff with a mysterious, yet brilliant bomber, Don and Charlie discover that he was poisoned to keep him from exposing a secret while the team are left reeling and stunned after learning that one of their own is a traitor... Mathematics used: Merkle-Hellman, Wheat and Chessboard Problem, straddling checkerboard, substitution cipher, Bacon's cipher, knapsack problem and Lorentz force

Season 4 (2007–2008)

For a more comprehensive list, see List of Numb3rs episodes (season 4).

No.	#	Title	Directed by	Written by	U.S. viewers (million)	Original air date	Production code
62	1	"Trust Metric"	Tony Scott	Ken Sanzel	9.38	September 28, 2007 (2007-09-28)	401
Having been captured as a Chinese spy, Colby escapes and is then interrogated on a boat traveling back to China. His friends have doubts but agree to a daring rescue. Mathematics used: Trust metric, set covering deployment, heuristics and Illumination problem
63	2	"Hollywood Homicide"	Alexander Zakrzewski	Andy Dettmann	9.76	October 5, 2007 (2007-10-05)	402
A girl turns up dead in a star's bathtub, leading the FBI team to uncover blackmail and murder while following his rescue, Colby rejoins the team. Mathematics used: Snell's law, Archimedes' principle and game theory
64	3	"Velocity"	Fred Keller	Nicolas Falacci & Cheryl Heuton	9.16	October 12, 2007 (2007-10-12)	403
When a street race leads to a bad accident in which a man is killed, the FBI find links to a cold case. Mathematics used: Angular momentum, centripetal force, conservation laws and Newton's laws of motion
65	4	"Thirteen"	Ralph Hemecker	Don McGill	9.85	October 19, 2007 (2007-10-19)	404
The team is on the trail of a serial killer who tortures his victims the way the 12 apostles died. A Cal Sci Religious Studies professor is brought in to explain the history and the numerology, which Charlie refuses to accept. Mathematics used: Fibonacci coding. See also: Numerology and Hebrew numerology
66	5	"Robin Hood"	J. Miller Tobin	Robert Port	9.70	October 26, 2007 (2007-10-26)	405
A private bank with several suspicious customers is broken into. David and Colby get their "groove" back. Charlie and Amita discuss her father's reaction to her dating a non-Indian. Mathematics used: Listing's law, projectile motion and dating system
67	6	"In Security"	Stephen Gyllenhaal	Sean Crouch	9.34	November 2, 2007 (2007-11-02)	406
A woman in witness protection is killed after going to dinner with Don. The lead suspect is also in witness protection. Charlie's book is released. Mathematics used: CART Analysis, Regression Analysis and Path Analysis
68	7	"Primacy"	Chris Hartwill	Julie Hébert	9.94	November 9, 2007 (2007-11-09)	407
A man is killed while playing an alternate reality game. Amita, a longtime player of the MMORPG side of the game gets put in danger when the killer sees her as his only opponent. Charlie does a TV interview about his book. Charlie asks Amita to move in with him. Mathematics used: Evolutionary algorithm
69	8	"Tabu"	Alex Zakrzewski	Sekou Hamilton	10.26	November 16, 2007 (2007-11-16)	408
A big businessman's daughter is kidnapped, but the whole game changes when he refuses to play along with the kidnappers. Megan deals with her issues with her father again. Mathematics used: Tabu search, minimax and Bayesian priors
70	9	"Graphic"	John Behring	Nicolas Falacci & Cheryl Heuton	10.12	November 23, 2007 (2007-11-23)	409
A comic-book convention becomes a crime scene when a deadly robbery leads to the disappearance of an extremely rare comic book. Mathematics used: Fractal Dimension Analysis, auction Theory and "Wrinkliness" (Detection of Handwriting Forgery)
71	10	"Chinese Box"	Dennis Smith	Ken Sanzel	9.75	December 14, 2007 (2007-12-14)	410
A paranoid gunman shoots an FBI agent at the FBI headquarters, then shuts himself and David in an elevator. Liz is leaving for a few weeks on a narcotics job. Mathematics used: Chinese room, "Chomp" and cluster analysis
72	11	"Breaking Point"	Craig Ross, Jr.	Andrew Dettman	9.81	January 11, 2008 (2008-01-11)	411
An investigative reporter goes missing, and an attempt is made to kill Charlie after he tries to help the FBI. Mathematics used: Regression Analysis
73	12	"Power"	Julie Hébert	Julie Hébert	10.08	January 18, 2008 (2008-01-18)	412
Don and the team track down an officer who has turned into a serial rapist. Mathematics used: Network theory and set theory
74	13	"Black Swan"	John Behring	Ken Sanzel	10.00	April 4, 2008 (2008-04-04)	413
The team takes down an inner-city meth lab, and while on the bust they also arrest a bystander who is discovered to have guns and other suspicious items in the back of his van. Mathematics used: Floyd-Warshall algorithm, Dirichlet tessellation, brute force and time series. See also: Black swan theory.
75	14	"Checkmate"	Stephen Gyllenhaal	Robert Port	9.54	April 11, 2008 (2008-04-11)	414
Don's old flame returns to California to prosecute an incarcerated criminal kingpin who seems to be ordering assassinations from within the prison. Don and team find themselves in a race against time to convince a teenage chess genius who may be the clue into finding how the orders are being sent. Mathematics used: supervised multiclass labeling, paper folding, diamond cut, chess and algebraic chess notation
76	15	"End Game"	Dennis Smith	Don McGill	9.64	April 25, 2008 (2008-04-25)	415
Don and his team hunt for an ex-Marine (Sharif Atkins) wanted for murder, while the ex-Marine's family is kidnapped. Mathematics used: OODA Loop and decision theory
77	16	"Atomic No. 33"	Leslie Libman	Sean Crouch	10.33	May 2, 2008 (2008-05-02)	416
A cult is poisoned with arsenic, but refuses medical help. Their new leader is trying to change that and other things about his church. When they find that the old leader was also poisoned with Arsenic, the mystery gets deeper. Mathematics used: Bayesian network analysis, Non-Newtonian fluid, social network analysis, affinity analysis and K-optimal pattern discovery
78	17	"Pay to Play"	Alex Zakrzewski	Steve Cohen & Andrew Dettman	9.33	May 9, 2008 (2008-05-09)	417
A rapper is killed after a celebration thrown by the record label. Megan is taking some time off and Charlie finally meets Amita's parents. Mathematics used: String metric and Gröbner basis
79	18	"When Worlds Collide"	John Behring	Nicolas Falacci & Cheryl Heuton	9.78	May 16, 2008 (2008-05-16)	418
Charlie and the FBI have their differences about a Pakistani charity group suspected of funding terrorism. Final appearance of: Megan Reeves. Mathematics used: Byzantine fault tolerance, Figure-Ground, Wallpaper group, M. C. Escher, Hyperbolic geometry and Six degrees of separation

Season 5 (2008–2009)

For a more comprehensive list, see List of Numb3rs episodes (season 5).

No.	#	Title	Directed by	Written by	U.S. viewers (million)	Original air date	Production code
80	1	"High Exposure"	Alex Zakrzewski	Nicolas Falacci & Cheryl Heuton	8.21	October 3, 2008 (2008-10-03)	501
Don and his team hunt for killers of two rock climbers found in possession of a large diamond. Charlie decides he should get his FBI clearance reinstated and a new agent joins the team.; First appearance of: Nikki Betancourt. Mathematics used: Percolation Threshold and geometrical analysis
81	2	"The Decoy Effect"	Ralph Hemecker	Ken Sanzel	8.01	October 10, 2008 (2008-10-10)	502
After a woman is murdered in what appears as an ATM robbery a series of kidnaps, rapes and murders turns into a hunt for the gang leader. New girl Nikki agrees to be the decoy, and Charlie's involvement leads to trouble for Don. Mathematics used: Decoy effect, Hall effect and scheduling algorithm
82	3	"Blowback"	Dennis Smith	Robert Port	8.68	October 17, 2008 (2008-10-17)	503
When eight people, including two LAPD police officers, are executed in a coffee shop, a detective (D. B. Woodside) gets the team on the case, and they uncover a trail of blackmail, romance and corruption. Also, McGowan's (Keith Carradine) investigation of Charlie and Don deepens. Mathematics used: Aggregation modeling and Hidden Markov model
83	4	"Jack of All Trades"	Stephen Gyllenhaal	Andrew Dettmann	9.33	October 24, 2008 (2008-10-24)	504
Don's team joins FBI Agent Bloom (Henry Winkler) in tracking an elusive con man. Meanwhile, decisions are announced on Charlie's FBI clearance and disciplinary action for Don. Mathematics used: Belief propagation
84	5	"Scan Man"	Craig Ross, Jr.	Don McGill	10.72	October 31, 2008 (2008-10-31)	505
The team hunts a crew stealing high-end goods from a shipping service and looks to an employee with savant-like abilities to lead them to those behind the scheme. Mathematics used: Geographic network, supply chain analysis and fractals
85	6	"Magic Show"	John Behring	Sean Crouch	11.28	November 7, 2008 (2008-11-07)	506
While on a date, David catches a disappearing act at a magic show but quickly becomes involved in the performance when the magician really vanishes. Mathematics used: Design Recovery
86	7	"Charlie Don't Surf"	Emilio Estevez	Steve Hawk	9.29	November 14, 2008 (2008-11-14)	507
One of Don and Charlie's friends dies in what is deemed an accident. Not convinced, the brothers investigate further. Mathematics used: Deconvolution, neural network, hyperspectral imaging and site-prediction modeling
87	8	"Thirty-Six Hours"	Rod Holcomb	Julie Hébert	11.30	November 21, 2008 (2008-11-21)	508
The team is sent to investigate and help with the recovery at a train crash; however, the train is carrying dangerous chemicals. During its original run, David Krumholtz gave a public service announcement stating that the episode was not in fact based on a similar train crash in the California area that occurred after taping, but before the episode aired. Mathematics used: Infotaxis and swarm robotics
88	9	"Conspiracy Theory"	Dennis Smith	Robert Port	9.88	December 5, 2008 (2008-12-05)	509
A bomb goes off during a high profile meeting and a documentary film maker has a conspiracy theory about it. Mathematics used: Simpson's paradox, Rationality theorem
89	10	"Frienemies"	Steve Boyum	Nicolas Falacci & Cheryl Heuton	9.18	December 19, 2008 (2008-12-19)	510
Charlie and his rival Marshall Penfield race against time to solve a case. Mathematics used: Group Dynamics and Three Way Duel
90	11	"Arrow of Time"	Ken Sanzel	Ken Sanzel	10.14	January 9, 2009 (2009-01-09)	511
A convicted criminal breaks out of jail, with thoughts of revenge. Don must face his past and turn to his new-found religious beliefs. Mathematics used: Hidden Markov model, Maxwell's Demon and the Viterbi algorithm
91	12	"Jacked"	Stephen Gyllenhaal	Don McGill	11.02	January 16, 2009 (2009-01-16)	512
When 18 tourists on a bus are taken hostage, the team has only four hours to stop the hijackers. Mathematics used: Articulate and Inverse Game Theory
92	13	"Trouble In Chinatown"	Julie Hébert	Peter MacNicol	10.96	January 23, 2009 (2009-01-23)	513
An undercover agent disappears, leading the FBI team deep into Chinatown's black market. The FBI gets help from the returning psychic Simon Kraft (John Glover). Mathematics used: Digital Signal Processing and Lévy flight
93	14	"Sneakerhead"	Emilio Estevez	Aaron Rahsaan Thomas	10.30	February 6, 2009 (2009-02-06)	514
When a pair of valuable sneakers is stolen from the vault of a foreign ambassador, the team delves into the world of sneaker collecting. Mathematics used: Pinball
94	15	"Guilt Trip"	Gwyneth Horder-Payton	Mary Leah Sutton	9.10	February 13, 2009 (2009-02-13)	515
When Robin's seemingly bulletproof case fails and a dangerous weapons smuggler is released, the team investigates the possibility of jury tampering. Mathematics used: Probability, Mersenne twister, scientific jury selection and social networking potential
95	16	"Cover Me"	Rob Morrow	Andrew Dettmann	9.62	February 27, 2009 (2009-02-27)	516
Liz works undercover to take a new illegal drug off the streets after Charlie predicts it is going to be the next big thing to hit the drug market. David is assigned to be her handler and he worries when she varies from his plan and puts her trust in a fellow undercover agent who may be an addict himself. Mathematics used: Supply & Demand Theory
96	17	"First Law"	Steve Boyum	Sean Crouch	10.12	March 6, 2009 (2009-03-06)	517
The FBI team investigates the death of visionary scientist Daniel Robertson; the prime suspect is Robertson's computer project, Baley. Charlie considers an enticing job offer. The title of this episode, as well as the name of one of its principle characters, is a nod to the work of Isaac Asimov, whose stories frequently revolved around the concept of machine intelligence. Mathematics used: Turing test
97	18	"12:01 AM"	Ralph Helmecker	Robert Port	9.51	March 13, 2009 (2009-03-13)	518
The FBI team rushes to track down evidence that could save a mob boss from the death penalty; new information comes in that could exonerate him, leaving the team with only hours to run down the new lead. Mathematics used: Light Refraction and Voice Analysis
98	19	"Animal Rites"	Ron Garcia	Julie Hébert	9.80	April 10, 2009 (2009-04-10)	519
The investigation into the death of a CalSci professor exposes possible links to animal rights extremists.
99	20	"The Fifth Man"	Ken Sanzel	Don McGill	8.82	April 24, 2009 (2009-04-24)	520
Things go terribly wrong when Don gets injured during an investigation. Charlie and Alan have to put things into perspective, when the thought of possibly having to lose a part of their family comes to face them.
100	21	"Disturbed"	Dennis Smith	Nicolas Falacci & Cheryl Heuton	9.70	May 1, 2009 (2009-05-01)	521
Charlie focuses his attention on tracking a previously undetected serial killer to help deal with his guilt over Don's almost-fatal stabbing. He receives help from a geeky amateur sleuth and a retired accountant, who each research serial murders as a hobby. The investigation reveals that the killer may be responsible for over two dozen unsolved deaths.
101	22	"Greatest Hits"	Stephen Gyllenhaal	Andrew Dettmann	9.57	May 8, 2009 (2009-05-08)	522
The team investigates a string of bank robberies and believe that ex-FBI Agent Roger Bloom (played by Henry Winkler) is responsible for them. Amita is abducted at gunpoint in front of Charlie in the last scene.
102	23	"Angels and Devils"	Alex Zakrzewski	Ken Sanzel	9.72	May 15, 2009 (2009-05-15)	523
When Amita is abducted by the leader of a cult with female followers, it will take Don, Charlie, the whole team, and even some outside help in the form of Ian Edgerton to get her home safely. At the end of the episode, Charlie proposes to Amita. Mathematics used: Angel problem and burr puzzle

Season 6 (2009–2010)

For a more comprehensive list, see List of Numb3rs episodes (season 6).

No.	#	Title	Directed by	Written by	U.S. viewers (million)	Original air date	Production code
103	1	"Hangman"	Ken Sanzel	Ken Sanzel	8.10	September 25, 2009 (2009-09-25)	601
While Charlie waits for an answer to the question he popped to Amita, Don and his team try to hunt down a sniper intent on killing someone under FBI protection. Mathematics used: Unexpected hanging paradox and Barberpole illusion
104	2	"Friendly Fire"	Rod Holcomb	Mark Llewellyn & Robert David Port	7.85	October 2, 2009 (2009-10-02)	602
Two members of a unit led by Don's former mentor are killed during a shootout with bank robbers. The bank robbers refuse to take responsibility of the killings and Charlie recreates the shootout to find out how they died. Larry does not want to take part in the search for the God particle. He also quits teaching. Mathematics used: Triangulation
105	3	"7 Men Out"	Alex Zakrzewski	Don McGill	7.34	October 9, 2009 (2009-10-09)	603
To find the person behind a deadly gambling ring that is running a high-stakes Russian roulette tournament, Don and his team are called in to investigate. Elsewhere, Don and Charlie become concerned over the financial health of Alan. Mathematics used: IP traceback
106	4	"Where Credit's Due"	Dennis Smith	Andy Dettmann	7.77	October 16, 2009 (2009-10-16)	604
The team investigates several deaths that turn out to be copies of a soon-to-be-released movie, while Larry goes on his own personal adventure. Alan continues his job search. Mathematics used: Triangulation
107	5	"Hydra"	Ralph Hemecker	Sean Crouch	8.05	October 23, 2009 (2009-10-23)	605
The team attempts to find the daughter of a geneticist whom they suspect was kidnapped by the unstable mother. However, they become concerned about the case when they find evidence that suggests the young girl was a clone. Meanwhile, Charlie and Amita discuss having kids and Liz reveals a dark secret. Its confirmed the girl was a clone and the geneticist didn't actually care about her beyond as a test subject. In the end, the team takes the girl from the men holding her for the geneticist's company and returns her to her mother, helping them flee the country. Mathematics used: Wavelets, Acoustics and Cake cutting
108	6	"Dreamland"	Stephen Gyllenhaal	Nicolas Falacci & Cheryl Heuton	7.74	October 30, 2009 (2009-10-30)	606
A woman's corpse turns up at a decommissioned air base. Mathematics used: Electric Fields for Three Point Charges, Cyclotrons and Gaussian Laser Modes
109	7	"Shadow Markets"	Julie Hébert	Julie Hébert	8.09	November 6, 2009 (2009-11-06)	607
In order to find a cyber crime lord, the team conducts an undercover sting. The operation is prevented by a brilliant hacker whose goal is to take over the Internet black market. However, his actions put him in a dangerous online war that might lead to murder.
110	8	"Ultimatum"	Dennis Smith	Robert David Port	8.16	November 13, 2009 (2009-11-13)	608
In the middle of a case where he is tracking down a criminal in charge of a heroin ring inside a prison, Agent Ian Edgerton unexpectedly turns into the murder suspect when the informant he meets with winds up dead, sending Edgerton over the edge when he takes a member of Don's team hostage. Mathematics used: Pursuit-evasion, Game theory and Ultimatum game
111	9	"Con Job"	Ralph Hemecker	Don McGill	7.84	November 20, 2009 (2009-11-20)	609
When robbers hit a diamond exchange and take hostages, Don and the team find an unlikely ally in convict John Buckley, who may help the team's investigation when they believe the men are copying Buckley's criminal strategies. Mathematics used: Packet injection, Man-in-the-middle attack and Combinatorial game theory
112	10	"Old Soldiers"	Ken Sanzel	Steve Cohen	7.38	December 4, 2009 (2009-12-04)	610
Agent Roger Bloom, who worked on the Cooper case, is brought in to help the team when they foil a robbery of an armored car full of Federal Reserve money and recover bills that trace back to the infamous D.B. Cooper heist. Mathematics used: Probabilistic risk assessment
113	11	"Scratch"	Stephen Gyllenhaal	Mary Leah Sutton	9.32	January 8, 2010 (2010-01-08)	611
The team investigates the theft of scratch-off lottery tickets, but the stakes are raised when one of the culprits killed at a botched robbery turns out to be a former lottery winner.
114	12	"Arm in Arms"	Gwyneth Horder-Payton	Andy Dettmann	9.65	January 15, 2010 (2010-01-15)	612
The team searches for a lost shipment of high-caliber firearms when one of the weapons is responsible for random killings throughout the city. Also, Charlie and Amita disagree on a wedding date while Don re-evaluates his relationship with Robin. Mathematics used: Reverse trajectory, 4D mapping, Combinatorial optimization and Pigeonhole principle
115	13	"Devil Girl"	Stephen Gyllenhaal	Julie Hébert	8.70	January 29, 2010 (2010-01-29)	613
The team searches for a serial killer who is targeting men that solicit prostitutes. Also, Colby and Nikki deal with the aftermath of a car crash when they have an accident during the investigation. Mathematics used: Geo-profiling and Scaled gradient projection
116	14	"And the Winner Is…"	Ralph Hemecker	Gary Rieck	9.18	February 5, 2010 (2010-02-05)	614
The team gets a taste of the limelight when they search for jewels worth millions that have been stolen during an awards show broadcast. In addition, Don revisits an old case that is haunting him, and Larry returns from his adventure in the desert. Mathematics used: Retrograde analysis and Crowd flux dynamics
117	15	"Growin' Up"	Rob Morrow	Robert Port	8.10	March 5, 2010 (2010-03-05)	615
The team investigates the deaths of two men who were part of a group of friends that had been sexually assaulted by a teacher when they were young boys.
118	16	"Cause and Effect"	Nicolas Falacci	Nicolas Falacci & Cheryl Heuton	8.74	March 12, 2010 (2010-03-12)	616
The team try to find Don's stolen gun, which is being used in a series of vigilante killings. Meanwhile, Charlie and Amita get married and Don decides on the direction he wants to take in life. Final appearance of: Don Epps, Charlie "Charles" Epps, Alan Epps, David Sinclair, Amita Ramanujan, Larry Fleinhardt, Colby Granger, Ian Edgerton, Robin Brooks and Nikki Betancourt.

References

General

• "Numb3rs Episodes". TV Guide. Retrieved February 20, 2009. 
• (Booklet) Numb3rs – Season 1 (Liner notes). CBS. 2006 [2005].
• (Booklet) Numb3rs – Season 2 (Liner notes). CBS. 2006 [2005–2006].
• "Numb3rs: Season 3". IGN. Retrieved February 17, 2009. 
• "Numb3rs: Season 4". IGN. Retrieved February 17, 2009. 
• "Numb3rs: Season 5". IGN. Retrieved February 17, 2009. 
• "Numb3rs: Season 6". IGN. Retrieved November 8, 2009. 

Specific

External links

• List of Numb3rs episodes at the Internet Movie Database
• List of Numb3rs episodes at TV.com