2. * A ratio is a comparison of two quantities by division. Ratios like 1 out of 2 can be written as 1:2, ½, or 1 to 2. * When ratios compare a number to 100 it can be written as a percent. * n/100 = n%

3. * The word percent (per cent) means per 100. * When a fraction has a denominator of 100, you can write the numerator as a percent * 47/100 = 47% * 4/5 = 80/100 = 80%

5. * To change from a decimal to a percent: *Multiply by 100* Move the decimal 2 places to the right and put a percent sign on the answer. * To change from a percent to a decimal: *Divide by 100* Take off the percent sign and move the decimal 2 places to the left.