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ACER Press author guidelines

Numbers and measurement

Numbers

Currency

Dates and time

Fractions and decimals

Units of measurement

Ordinal numbers

Numbers

In running text, use numerals for ‘2’ and above. Spell out the numbers ‘zero’ and ‘one’ in words.

There are some exceptions where words should always be used for numbers:

  • at the start of a sentence
  • for fractions in running text (for example, two-thirds)
  • for proper nouns that include numbers written as words
  • for figures of speech.

Write all numbers as numerals in:

  • tables
  • mathematical content
  • dates and times
  • scientific content
  • measurements.

Use a combination of numerals and words for large rounded numbers.

Example

2.5 million

Use commas in numbers with 4 or more digits.

Examples

2,500

25,000

250,000,000

En dashs (–) can show spans or ranges when used with numerals. Avoid the use of en dashes in running text. Instead, use phrases, such as ‘from’ and ‘to’ or between and ‘and’.

En dashes should only be used to indicate spans where space is limited or in more technical content.

Currency

Use symbols and numerals for amounts of money. Do not put a space between the currency symbol and the numeral.

Example

$25.50

Dates and time

Follow Australian conventions for dates and time.

Spell out days of the week and months and only use abbreviations if space is limited.

Example

Thursday 7 October 2021

Numeric dates should be presented in the format day/month/year.

Use lower case for centuries and spell out in full unless there is limited space.

Use CE for the time before the common era (CE) and BCE for the time before the common era (BCE).

Use a colon between hours and minutes and ‘am’ and ‘pm’ (without full stops). These should be included with a non-breaking space after the number. Two zeros can be used to show the hour, but this is not essential.

Example

10 am or 10:00 am

Fractions and decimals

Use words for fractions in general text. Use a hyphen in ‘one-third’, ‘one-fourth’, and so on.

Example

One-third of all Australian students are able to perform complex calculations in algebra.

If a number is less than one, ensure that a zero precedes the decimal point.

Example

0.5 cm, not .5 cm.

Use decimals when precision is required.

Units of measurement

Spell out units of measurement in your main text.

Examples

one metre, not 1 m

300 kilometres, not 300 km

25 square kilometres, not 25 km2

Exceptions include publications where the text contains many units of measurement and spelling them out would be cumbersome. Whether you decide to spell out or to use symbols, be consistent.

Note the space between the unit of measurement and its numerical quantity, the absence of an ‘s’ in the plural and the absence of full stops: for example, 14 ml, 8 cm, 9 km. Note, there is no space in 45% or 63ºC.

Figures should always be used with unit of measurement symbols.

Examples

25 km, not twenty-five km

245 cm, not two hundred and forty-five cms.

Use ‘percent’ throughout your main text where figures occur occasionally. Use the % symbol with no space where percentages are quoted extensively and in tables.

Ordinal numbers

Ordinal numbers show the order of something in a sequence.

Examples

first, second, third, 10th 11th

Spell out ordinal numbers up to ‘ninth’. After this, use numerals with the relevant suffix.

Do not use ordinal numbers for dates.