## Percent Of a Number

Click on the image at right to get the lesson app with instructor notes.

In this lesson, students review multiplying fractions by whole numbers (5.NF.B.4a) in mathematical and real-world contexts, with the fraction in this case being a percent—a fraction with a denominator of 100. Students thus learn how to determine the percent of a number. Students also practice converting percents into fractions in simplest form. A mental math method of working with percent-of problems is also covered.

## Module 1 Video

This video begins with three examples of "value of a number" constructions to show that they all involve multiplication—2 of the boxes, one half of a box, and 30% of a box. A percent is defined as a ratio with a denominator of 100. So, 100% is 100/100, which is equal to 1. Thus, students can use percents like fractions (which are part-to-whole ratios).

I make a fantastic mistake at the end of this video. See if your students can catch it. (I say that 1% of the box of shoes is 1 shoe. This can't be right, since 30% is 3 shoes. One percent of the box is actually one tenth of a shoe.)

## Module 2 Video

In this video, a percent-of problem is modeled, followed by a problem of the form A is B% of what number—a problem involving determining the whole given a part and percent.
percent of
Finding the percent of a whole number.
6-RP.A.3c