Punctuation in numbers

Punctuation in numbers can be very tricky. Numbers can take the form of dates, time, numbers, decimals, etc. Punctuating one of those forms may require the use of many punctuation marks.


Full stops or slashes are often used in dates.

American usage
12.3.09 3/12/09
2.28.15 2/28/15

Scientific usage

Full stops are not used in scientific abbreviations.

12 kg 50 cm


Full stops and occasionally colons are used in times.

4.15 p.m. 21.15
3:30 a.m. 20:30

Long numbers

Commas are used in numbers to mark off units of thousands and millions.

1,359 2,543,678


Full stops indicate decimal points.

1.5 25.08
Dash (Prev Lesson)
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