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Representation of numbers and numerical values

The decimal sign shall be a comma. The thousand separator shall be a space.

NOTE 1: In the text below, ° represents the non-breaking space character.

If a value less than 1 is written in decimal form, the decimal sign shall be preceded by a zero.

EXAMPLE 1: 0,001.

Each group of three digits reading to the left of a decimal sign shall be separated by a space from preceding digits or following digits respectively, except for four-digit numbers designating years.

EXAMPLE 2: 23°456 2°345 2,345 2,345 6 2,345 67 but the year 1997.

For clarity, the symbol × or a lower case x (rather than a point or any other symbol) shall be used to indicate multiplication of numbers and numerical values.

EXAMPLE 3: Write 1,8°×°10-3 (not 1,8 * 10-3 or 1,8 • 10-3 or 1,8 . 10-3).

NOTE 2: The exception are vector values because it makes a difference whether multiplying with a "×" (scalar value) or with a "•" (vector value).

To express numbers of items (as opposed to numerical values of physical quantities), the numerals one to nine shall be spelt out in full.

EXAMPLE 4: "Carry out the test on five tubes, each 5 m long."

EXAMPLE 5: "Select a further 15 tubes for the pressure test."

Preserve document identities as in the original titles.

EXAMPLE 6: ISO/IEC°10531-1 (not ISO/IEC 10°531-1).

EXAMPLE 7: ES°201°150.

Put a non-breaking space between a number and its unit - including the percent sign (%) - even if the unit is not abbreviated:

EXAMPLE 8: 2ºpages 4ºseconds 15º%.

Write a number preceded by a unary operator (sign) without an intervening space, except for ≤, ≥, >, <:

EXAMPLE 9: a level of -3°dB …

EXAMPLE 9a: > 3 dB

Put a non-breaking space both before and after binary operators (+, -, ×, etc.):

EXAMPLE 10: a°+°b°=°c.

Use non-breaking spaces ("Ctrl" + "Shift" + space) for the thousand separator, before and after binary operators and preceding units.

Use a non-breaking hyphen for the minus sign:

  • For AZERTY keyboard ("Ctrl" + 8)
  • For QUERTY keyboard "Ctrl" + "Shift" + "hyphen (_)