Teaching Models

Understand Percent

Percent
A percent is a ratio of a number to 100. Percent means “per hundred.” Thus, 20 percent or 20% means twenty-one-hundredths. A percent can be written as a fraction or a decimal. At this grade level, students are introduced to fractional percents, such as 2.5%, as well as percents greater than 100%, such as 250%.

To change a percent to a decimal, write the percent amount and move the decimal point 2 places to the left. To change a decimal to a percent, write the decimal, move the decimal point 2 places to the right, and add the percent sign. To change a percent to a fraction, use the given percent as the numerator of a fraction with 100 as the denominator, and then reduce the fraction to simplest form. One way to change a fraction to a percent is to write an equivalent fraction with a denominator of 100 and then change it to a percent.

Examples:

20% = 20/100 = 1/5

Comparisons of fractions, decimals, and percents can be completed in several ways, including locating each on a number line, rewriting each as a fraction with a common denominator, or rewriting each as a decimal.


Teaching Model 17.3: Compare and Order Ratios, Decimals, and Percents


Houghton Mifflin Math Grade 6