Percents: Tips and Tricks
- Whenever possible, connect percents to visual models such as a 10 x 10 square grid or a meterstick.
- Be sure your students understand that a percent is a ratio; for example 35% =
. - Frequently remind your students that the word percent is a synonym for hundredths. For example, 36% can be written as the fraction
or as the decimal 0.36. - Make sure your students remember some familiar conversions of percents to fractions or decimals; for example, 10% =
, 25% = 
, 50% = 
, 75% = 
, 33 
% = , and 66 
% = . - Suggest that students estimate the answers to problems as a way of checking the reasonableness of their answers. For example, if they want to find 24% of $82, they can estimate that 24% is close to 25%. Since 25% is equal to , and of $80 = $20, 24% of $82 is about $20.
- Remind students that when you divide by 100, you simply move the decimal point two places to the left. For example, 35% is 0.35 when written as a decimal.
- Encourage students to use mental math when calculating with percents. For example, to find 15% of a number, find 10% first and then take half of that and add it on. So, 15% of $120 = 10% of $120, or $12, plus 1/2 of $12, or $6, which added together equals $18.