5. Mechanics of Writing

A *number *is a characteristic that describes a unit within a collection. A number is expressed by *numerals* (1, 2, 3, 4) or by words. *Cardinal numbers* use words such as "one, two, three," while *ordinal numbers* use words such as "first, second, third."

In computer documentation, you will most often use numerals when numbers are discussed in text.

Spell out:

- Numbers from zero through nine, unless the number is part of a measurement

three computers (a count)

3 inches (a measurement)

- Approximations

You can choose from hundreds of applications for your computer.

- Extreme values, such as "million" and "billion," but precede them with a numeral

3 million instructions per second

- Any number that begins a sentence

Ten files are required.

- The first number if a numeral immediately follows the number

Print twelve 500,000-byte files.

Use numerals for:

- Numbers 10 or greater

- Numbers less than 10 if they are of the same type and appear in the same paragraph as numbers of 10 or greater

The menu offers 11 options, but you will use only 4.

- Negative numbers

- Most fractions

- All percentages

- All decimals, including the leading zero

0.15

1.25

- All measurements

6 pounds

3.5-inch disk drive

- Chapter, section, part, page, figure, and table numbers

Part 4

Chapter 6

Numbers and numerals generally require the same punctuation as words. Punctuating numbers and numerals becomes troublesome, however, when they are compounded.

- Do not hyphenate numbers or numerals when they serve as single modifiers.

Your file comprises 500,000 bytes.

- Hyphenate numbers or numerals in compound modifiers.

Print your 500,000-byte file.

- Do not use a comma in numerals of four digits.

1028 6000

- Use a comma in numerals of more than four digits.

10,000 600,000

The usage of numerals for fractions depends upon the context. Sometimes spelling out the fraction or using decimals is the preferred form.

- Use numerals for fractions in tables and for units of measurement, but spell out common fractions in running text.

1/2-inch tape drive

half the users in the test

- Use a space between a numeral and its related fraction.

8 1/2 inches

- If a fraction is being used as a modifier, insert a hyphen between the fraction and what it is modifying.

8 1/2-inch width

- Use decimals when that is the industry standard.

5.25-inch drive

3.5-inch diskette

1/2-inch tape drive

- Spell out a numeric modifier of a fraction.

ten 1/2-inch tape drives (10 tape drives for 1/2-inch tape)

10 1/2-inch tape drive (tape drive for 10 1/2-inch tape)