Definition
Colon
In ratio notation, a colon is the : symbol placed between two ordered quantities.
What it means
Read 3:5 as “three to five.” The colon is the separator in the middle. It keeps the first quantity first and the second quantity second, so swapping the numbers gives a different ratio.
Remember it
The colon is the “to” between two ratio amounts.
Example
A bag has 4 red counters and 7 blue counters. Red to blue is 4:7. The colon separates 4 and 7; it does not join them into 47.
Watch for
This card owns the ratio-notation sense. A colon in a sentence, a time such as 3:45, or an anatomy word has a different meaning.
Common mix-up
The colon separates the ratio terms, but the order of those terms still matters.
Exact meaning
In ratio notation, a colon is the symbol : used to separate the two ordered terms of a ratio.