English Grammar Review
Special Topics


There are many rules about how to write numbers. Here we will work through the situations where people make most of their errors with numbers written with digits.

Large numbers

When space is tight, and when you don't want to overwhelm the reader, abbreviate large numbers.

42K = 42,000
[K = kilo = thousand]

80.7M = 80,700,000
[M = mega = million]

2.54G = 2,540,000,000
[G = giga = billion]

Adjacent numbers

When two numbers in digits are adjacent in a sentence, separate them with a comma.

In 2018, 20% of our customers were from Germany.

On page 57, 3 photos of Cologne are provided.

By June 12, $90 will be deposited by Mr. Goetz.

Also, when one of the numbers is a hyphenated expression, write the first number out in words. Or write the second one out in words if it saves space.

5 3-hour meetings
[not good]

five 3-hour meetings
(but it does sound exhausting)

520 7-page booklets
[not good]

five hundred and twenty 7-page booklets
[too long]

520 seven-page bookets


In most writing at work, express percentages as digits followed by the word percent.

"Baseball is 90 percent mental," Mr. Berra said. "The other half is physical."
(He was a funny man.)

Do not place a hyphen in between a number and the word percent.

Siegfried was expecting a 20-percent discount.

Siegfried was expecting a 20 percent discount.

Note: Instead of the word percent, use the % symbol in technical writing, statistical data, forms, and tables.


Always write decimals in digits. It's okay to include commas in the left side for the whole number, but do not do so in the right side, in the decimal part.

[not okay]


Also, when there is only a decimal part to the number, use a zero in the whole number part.

.58 gram
[not okay]

0.58 gram


Use an en dash, or hyphen, to link two numbers in digits to represent a continuous sequence or range, except when the range is introduced by the word from or the word between.

Read pages from 35-38.

Read pages from 35 to 38.

Read pages between 35-38.

Read pages between 35 and 38.

Read pages 35-38.


To form the plurals of numbers in digits, add an s only.

Anna attended Leipzig University in the 1990's.
[not good]

Anna attended Leipzig University in the 1990s.

Lesson: Numbers
Module: Special Topics
Course: English Grammar Review