The term percent means per hundred or divide by one hundred. It can be substituted for the term hundredth in fractions and decimals. For example, 56/100 = 56% and 0.23 = 23%. A good model for percents is a square grid divided into 100 equal parts. Twelve of the 100 parts in the square below are shaded to show 12 hundredths (12/100, 0.12) or 12%.
Money is another good model for percent because there are 100 cents in a dollar. Thirty-seven cents ($0.37) is 37 hundredths (37/100) or 37% of a dollar. Six cents ($0.06) is 6 hundredths (6/100) or 6% of a dollar.
You can also use a meter stick to model percent. There are 100 centimeters in a meter, so 5 centimeters is 5 hundredths (0.05) or 5% of a meter. Twenty-three centimeters is 23 hundredths (0.23) or 23% of a meter. Provide students with many opportunities to see the relationship between percents, fractions, and decimals.As a prerequisite to computing with percents, an understanding of how to change fractions, decimals, and percents to satisfy a problem needs to be acquired.
- To change a decimal to a percent, multiply by 100 and write a % sign after the number.
100 ---> 45%
2/5 ---> 2 ч 5 ---> 0.4 ---> 40%
"A coat is on sale for 20% off the original price of $85. What is the amount of the discount?" In this problem you know the regular price and the rate or percent of the discount. You need to find the amount of the discount. (When computing with percent, remember to change the percent to a fraction or decimal.)
A = p