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The standard introduces the International System of Quantities (ISQ). It is a style guide for the use of physical quantities and units of measurement, formulas involving them, and their corresponding units, in scientific and educational documents for worldwide use. In most countries, the notations used in mathematics and science textbooks at schools and universities follow closely the guidelines in this standard.
The ISO/IEC 80000 family of standards was completed with the publication of Part 1 in November 2009. 
The standard has 14 parts: 
|ISO 80000-1 ||2009||General||ISO 31-0, IEC 60027-1 and IEC 60027-3||under review|
|ISO 80000-2 ||2009||Mathematical signs and symbols to be used in the natural sciences and technology||ISO 31-11, IEC 60027-1||under review|
|ISO 80000-3 ||2006||Space and time||ISO 31-1 and ISO 31-2||under review|
|ISO 80000-4 ||2006||Mechanics||ISO 31-3||under review|
|ISO 80000-5||Thermodynamics||ISO 31-4||under review|
|IEC 80000-6||Electromagnetism||ISO 31-5, IEC 60027-1|
|ISO 80000-7||Light||ISO 31-6||under review|
|ISO 80000-8||2007||Acoustics||ISO 31-7||under review|
|ISO 80000-9||Physical chemistry and molecular physics||ISO 31-8||under review|
|ISO 80000-10||Atomic and nuclear physics||ISO 31-9 and ISO 31-10||under review|
|ISO 80000-11||Characteristic numbers||ISO 31-12||under review|
|ISO 80000-12||Solid state physics||ISO 31-13||under review|
|IEC 80000-13||2008||Information science and technology||subclauses 3.8 and 3.9 of IEC 60027-2:2005 and IEC 60027-3|
|IEC 80000-14||Telebiometrics related to human physiology||IEC 60027-7|
International System of Quantities
Part 1 of ISO/IEC 80000 introduces the International System of Quantities and describes its relationship with the International System of Units (SI). Specifically, its introduction states "The system of quantities, including the relations among the quantities used as the basis of the units of the SI, is named the International System of Quantities, denoted 'ISQ', in all languages.", and further clarifies that "ISQ is simply a convenient notation to assign to the essentially infinite and continually evolving and expanding system of quantities and equations on which all of modern science and technology rests".
Units of ISO/IEC 80000
The standard includes all SI units but is not limited to only SI units. Units that form part of the standard and not the SI include the units of information storage (bit and byte), units of entropy (shannon, natural unit of information and hartley), the erlang (a unit of traffic intensity) and units of level (neper and decibel). The standard includes all SI prefixes as well as the binary prefixes kibi-, mebi-, gibi-, etc, originally introduced by the International Electrotechnical Commission to standardise binary multiples of byte such as mebibyte (MiB), for 10242 bytes, to distinguish them from their decimal counterparts such as megabyte (MB), for precisely one million (10002) bytes. In the standard, the application of the binary prefixes is not limited to units of information storage. For example, a frequency ten octaves above one hertz, i.e., 210 Hz (1024 Hz), is one kibihertz (1 KiHz).
A 1999 addendum to IEC 60027-2 on binary prefixes has resulted in public interest in the standard and is still being widely discussed in the computer community, as it provides a clear framework of prefixes that resolve the discrepancy and resulting confusion of using, e.g., a kilobit to indicate 1000 bits (1 kbit) or 1024 bits (1 Kibit).
The harmonized IEC 80000-13:2008 standard cancels and replaces subclauses 3.8 and 3.9 of IEC 60027-2:2005, those defining prefixes for binary multiples. The only significant change is the addition of explicit definitions for some quantities.
- International Vocabulary of Metrology
- International System of Units
- BIPM — publishes freely available information on SI units
- NIST — official U.S. representative for SI; publishes freely available guide to use of SI
- Standards Catalogue TC/12 Quantities and Units
- BSI/ISO Standards
- Standards and projects under the direct responsibility of ISO/TC 12 Secretariat
- "ISO 80000-1:2009". International Organization for Standardization. Retrieved 20 July 2013.
- "ISO 80000-2:2009". International Organization for Standardization. Retrieved 1 July 2010.
- "ISO 80000-3:2006". International Organization for Standardization. Retrieved 20 July 2013.
- "ISO 80000-4:2006". International Organization for Standardization. Retrieved 20 July 2013.
- BIPM SI Brochure
- ISO TC12 standards — Quantities, units, symbols, conversion factors
- NIST Special Publication 330 — The International System of Units
- NIST Special Publication 811 — Guide for the Use of the International System of Units