Write the quantities in the same units
Put the first quantity before the colon
Put the second quantity after the colon
Simplify both numbers by dividing by the greatest common factor
Keep dividing until no common factor remains
Example: 8:12 becomes 2:3
Example: 15:5 becomes 3:1
To compare two ratios, convert them to the same denominator or simplify both first
To find one part of a ratio, add all parts and divide the total by the sum of the ratio parts
To scale a ratio, multiply or divide both parts by the same number