Clear Technical Writing

Special Topics

In non-technical writing, we often use full words for numbers.

We arrived **three-quarters** of an hour ago and found **seven** swans swimming on the pond. **Twelve** days from now there will be about **eighty**.

We express numbers in digits almost all the time in technical writing.

For your writing to be clear, you must be *consistent* with your use of numbers and units of measurement.

**Be consistent with conventions**

Use digits when using the symbols *%* or *$*, and attach the symbol to the number.

The **$5** charge was a **10%** increase.

Use digits when using the abbreviations *a.m.* or *p.m.*

We attended the **10 a.m.** meeting.

Use digits when identifying a date.

On April **1**, pranksters write April __one__.

Always put a space between a number and its unit of measurement.

It weighs **50 kg**.

Never indicate a plural quantity by adding an *s* to a unit of measurement.

[x] It weighs 50 __kgs__.

Use lower-case letters for units of measurement, except for letters that stand for a person's name and for letters that indicate a multiplier greater than 1000.

At 120 **V**, the 1.5 **hp** motor drew 10 **A**.

[Alessandro Volta, Andre Ampere]

The wind turbine produces 10 **kW**.

[James Watt]

My radio is tuned to 89.3 **MHz**.

[Heinrich Hertz]

Use the abbreviation *No.* for the word *number* in front of a number in digits.

We are **No.** 1 in sales for **No.** 2 pencils.

When a number is preceeded by a word like *Box*, *Check*, *Invoice*, or *Room*, do not use the abbreviation for *number*.

I included **Check** 835 for **Invoice** 2106.

Note: Using *no.* instead of *No.* is prefered in some technical communities.

**Be consistent with yourself**

When you create your own abbreviation or unit of measurement, define it before using it and be consistent with conventions and with yourself.

If it's heavier than 45 kg, it's designated an extra-heavy parcel (xp). The distribution warehouse ships more than 20 __XPs__ per shift.

If it's heavier than 45 kg, it's designated an extra-heavy parcel (xp). The distribution warehouse ships more than 20 **xp** per shift.

Edit your writing by spotting problems with numbers and units of measurement.

We paid the
$ 860
charge on
January tenth
at
four p.m.
It was a
fifteen %
increase over what we paid last year for a
3hp
fan.
Please deliver it to
Room No. 2
in our laboratory.

Lesson: Numbers and Units

Module: Special Topics

Course: Clear Technical Writing