|1 000 000||one million||millionth||1 000 000th|
|1 000 000 000||one billion||billionth||1 000 000 000th|
Words or figures?
A common rule for writing numbers is to write one, two, three, four, five, six, seven, eight, nine and ten as words, but larger numbers as figures.
The following numbers may also be written as words in normal text:
Approximate versus exact
Compare also the examples below where words are used for approximate amounts and figures for exact values:
There have been over fifty new cases this year.
There have been 54 new cases this year.
There are around five thousand new students every year.
Last year there were 5023 new students.
Use figures with units or abbreviations
|6 mm||100 km|
|25 °C||pH 7|
Use figures with page, figure and table numbers
|page 1||p. 100|
|Figure 6||Fig. 8|
Use figures with dates
|19 February 2014|
|October 11, 2015|
Avoid beginning a sentence with a figure
In university and research writing you should avoid beginning a sentence with a figure, for example:
1 in 10 pregnancies …
Better: One in ten pregnancies …
2.5 mg of distilled water were added after 30 minutes …
Better: After 30 minutes, 2.5 mg of distilled water were added …
50% of students at some UK universities come from private schools …
Better: Fifty percent of students at some UK universities come from private schools …
Avoid mixing words and figures
Where possible, avoid mixing words and figures in the same sentence, particularly when comparing. For example:
Compulsory education in Britain is from five to 16, though many children begin preschool at 3 or four.
Better: Compulsory education in Britain is from 5 to 16, though many children begin preschool at 3 or 4.
However, where necessary numbers should be written as words or figures to avoid ambiguity, for example:
three 5-point scales
five 10-year-old children
Values over a million
Some values over a million, particularly currencies, may be written as a combination of figures and words, particularly when round figures:
USD 10 billion
Similarly with populations:
The population of the UK is around 60 million.
In English, do not add –s to specific multiples of a hundred, thousand, million or billion. For example:
two hundred (not two hundreds)
three thousand (not three thousands)
four million (not four millions)
five billion (not five billions)
However, an -s is indeed added to the general multiples hundreds, thousands, millions and billions:
Hundreds of researchers attended this year’s conference.
Thousands of people die of preventable diseases every day.
The cost may run into the millions, even billions.
In British English, when pronouncing numbers over 100 or writing them in words, and is always added before any units under 100:
|110||one hundred and ten|
|125||one hundred and twenty-five|
|150||one hundred and fifty|
|175||one hundred and seventy-five|
Multiples of a thousand are marked by a space or comma. A common rule in university and research texts is to write numbers under 10 000 without commas or spacing, and numbers 10 000 and over with commas or spacing. Some authors and publishers also divide four-figure numbers, for example 3 987 or 3,987.
|3987 or 3 987||3987 or 3,987|
|6 728 349||6,728,349|
A space is less ambiguous as the comma is used in some countries as the decimal symbol, for instance 3,142. As always, be consistent throughout your text and follow any guidelines for your subject or publication.
Do not use a point to mark thousands
In English, unlike some languages, the point is not used to mark thousands:
3.500 means 3½, not 3500
Do not add commas or spaces in page numbers
page 1234, not page 1 234 or page 1,234
Beware of ambiguity when reading or writing billion in British English:
Although billion is now normally used in British English to mean a thousand million (109) as in US English, it also has an earlier meaning of a million million (1012).
Decimals in English are indicated by a point, not a comma as in some languages. For example:
|a quarter or fourth||0.25|
If you normally use a comma for decimals in your country, be sure to carefully check your figures in English as this is a potential source of major error.
Common, single fractions do not need a hyphen:
|¼||one quarter or fourth|
But others generally do:
|¾||three-quarters or three-fourths|
The British spelling is per cent as two words and the US spelling percent as one word, though this is not a hard-and-fast distinction.
You should be consistent in your text in your use of %, per cent or percent:
|ten per cent||ten percent|
|10 per cent||10 percent|
|10%||not ten %|
The % symbol should always be written next to its number without a space:
Not: 100 %
Be consistent in the spacing of symbols in your text, for example:
1 + 1 = 2
5 − 3 = 2
On your computer, use the minus sign rather than a hyphen (-) or en dash (–), as these can be separated from their number at the end of a line. This is also the case for superscripts. The correct minus sign stays with its number even at the end of a line.
Roman numerals are sometimes used in university and research writing, for example for the preliminary pages of a book and sometimes for chapter numbers and bullets.
|Arabic Numeral||Roman Upper Case||Roman Lower Case|
How to calculate Roman numerals
Add numbers after a symbol of equal or greater value:
XX = X + X = 20
CX = C + X = 110
Subtract numbers before a symbol of greater value:
IX = X – I = 9
XC = C – X = 90
Greek and Latin numerical affixes
|Numerical Value||Greek or Latin|
|2||di, bi, du|
|semi, demi, hemi||half|
|multi, poly||much or many|