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Numbers, units and operators

Numbers, units and operators are used frequently in articles. We often quote the incidence of a condition as a range or say that x happens in more than y% of cases.

To try and keep the style similar across the site, and maximise the readability of these figures, we have some simple suggestions.

Numbers

In general:

  • under 10: if a number is less than 10, use full text, e.g. four
  • over 10: if a number is over 10, use digits, e.g. 5000
  • thousands separators can be helpful for very big numbers and as a rule of thumb we advise to use a comma for numbers larger than 10,000, e.g. 10,700,000.
  • decimals: don't go crazy, more than 2 is usually a special case, e.g. 1.76
  • fractions: no spaces either side of the slash, e.g. 1/4
Ranges

When ranges are included there should be no space either side of the dash, e.g. "22-27".  If the range is described within prose, there should be no dash, e.g. "the mean length is between 10 and 15 centimeters", not "the mean length is between 10-15 cm). Notice too, that the unit should be included in full if used in prose.

When giving a range, especially percentages, it is useful to pick a mean or median value that is representative of the range and then include the range in brackets after. Please see note on figures and percentages for further details and examples. 

Units

When using units, there should always be a space between the number and unit. This stems from the fact that the number is a numeric representation of a word and you would never not have a space between two words.  If the number is written in text, the unit should be written in full:

  • two millilitres
  • 15 ml (remember that it is ml, not mls)

Operators

  • where a percent sign is used, it should not have a preceding space, e.g. "22%"
  • where an operator is used, it should not have a space after it, e.g. "<45"

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