Numeric keypads usually operate in two modes: when Num Lock is off, keys 8, 6, 2, 4 act like arrow keys and 7, 9, 3, 1 act like Home, PgUp, PgDn and End; when Num Lock is on, digits keys produce corresponding digits. On Apple Macintosh computers, which lack a Num Lock key, the numeric keypad always produces only numbers. The Num Lock key is replaced by the Clear key.

The arrangement of digits on numeric keypads with the 7-8-9 keys on top and 1-2-3 keys on the third row is derived from calculators and cash registers. This is notably different from that of telephone Touch-Tone keypads which have the 1-2-3 keys on top and 7-8-9 keys on the third row. Some think that the layout for the early american telephone keypads was arranged this way so that the addition of the alphabetical characters followed the digits numerically. Some people experience the difference in layout as a confusing annoyance.[citation needed]

Numeric keypads are useful for entering long sequences of numbers quickly, for example in spreadsheets, financial/accounting programs, and calculators. Input in this style is similar to that of a calculator or adding machine.

## Measuring speed

Ten key speed is measured in Keystrokes per Hour (KPH). The minimum required speed for many data entry jobs is around 9000 KPH with good accuracy. A speed of 12,000 is considered excellent.[citation needed]

## Chinese input methods

The numeric keypad is used by some systems for input of Chinese characters, for example CKC Chinese Input System and Q9 input method.

## Computer games

A 104-key PC US English QWERTY keyboard layout with the numeric keypad at the far right.

Numeric keypads are also used for playing some computer games where the player must control a character, for example roguelikes. Unlike arrow keys, the numeric keypad allows diagonal movement. For keyboards without a numeric keypad, some games provide alternative movement keys, such as classic Rogue's HJKL keys.

The numeric keypad can also be an alternative to the WASD keys for navigation in computer gaming. This can be an attractive option for left-handed people who prefer to use the mouse with their left hand.