A ratio is the comparison between two quantities.

There are three ways to express a ratio:

1.) as a fraction

2.) as two numbers separated by a colon (:)

3.) as two numbers separated by the word "to"

Write the ratio of the lengths of two pieces of string: the shorter piece is 2 feet long, and the longer piece is 6 feet long.

A ratio is in simplest from when the two numbers do not have a common factor. Note that in a ratio, the units are not written.

3.) 2 feet to 6 feet = 2 to 6 = 1 to 3