Ratio

A ratio compares two quantities multiplicatively. It can be written as a : b, a/b, or "a to b".

A ratio describes a relationship, not a count. The ratio 2 : 3 says that for every 2 of the first quantity there are 3 of the second, whatever the actual amounts. Multiplying both parts by the same number gives an equivalent ratio.

Ratios are shown on a double-number-line or in a ratio table, and a ratio with a second term of 1 is a unit-rate.