In an earlier lesson, students learned that multiplying by a fraction can result in three different kinds of answers. The answer can be larger than the starting number, smaller than the starting number, or equal to the starting number, depending on whether the fraction is larger than one, equal to one, or less than one.
Since a percent is just another way to write a fraction with a denominator of 100, the same thing applies to multiplying by a percent. The operation can produce any of the same three results. The product can be larger than the starting number, equal to the starting number, or less than the starting number.
In this lesson, students make judgments about the effect of multiplying by different percents without doing the multiplication. They indicate whether the result of doing the multiplication would be a number that is greater than, equal to, or less than the starting number.
In earlier lessons, students have learned that a “fraction of” a number is the fraction multiplied by that number. They have also learned that percents are just another way to write certain fractions.
In this lesson, students combine and extend that knowledge to “percent of” situations in which some percent of a number is calculated.
To solve these problems, the percent is first converted to a decimal (which is just another way to write a fraction), then the decimal is then multiplied by the number.
In earlier lessons, students have learned to find a fraction of a number by multiplying the fraction by the number.
In this lesson, they extend their knowledge to include situations in which the fraction is written as a percent. In other words, the percent of a number is the same as a fraction of a number. That means to find the percent of a number, you first convert the percent to a fraction, then find the fraction of that number by multiplying the fraction times the number.