Derbyshire police officers have become the first in Britain to get a new educational booklet, which includes tips on how to spell.
Superintendent Gary Knighton has distributed the Fast Facts for Policing booklet to all 1,800 officers in the county.
It contains multiplication tables and the correct spellings of the days of the week and months of the year.
The differences between source and sauce, whether and weather and two and too are explained. And officers are advised on how to use the 24-hour clock.
Supt Knighton said: "Spellings and terminology are very important in our line of work and accuracy is key when producing official documents. We're pleased to be the first force to offer people the opportunity to improve their skills in this way and we hope other constabularies will consider distributing the Fast Facts booklet."
A Derbyshire police spokeswoman said only six of the booklet's 28 pages contained spelling advice.
"It's words that are commonly misspelt, not just by officers but by people in general.
"These guides are produced for various groups so some elements and pages are generic," she added.
The National Institute of Adult Continuing Education has produced similar pocket-sized booklets for plumbers, manual workers and hospital domestic staff.