Definition
exactly, precisely, or in a formulaic way.
Origins
The origin of this phrase goes back to the American Revolutionary War where a book containing numbered positions for rifle and bayonet practice was used to train soldiers. In the book, each diagram was numbered.
Also Said As
- by the book
- by numbers
See Also
- paint-by-numbers
How People Actually Use It
Following an exact procedure while doing something.
"Make sure everything goes by the numbers."
Source: Urban Dictionary