# Lesson 16

Finding the Percentage

### Lesson Narrative

While students have found percentages with easy numbers before now, in this lesson they will develop a general structure (MP7) that will work for any numbers.

### Learning Goals

Teacher Facing

• Critique or justify (orally) statements about percentages and equivalent numerical expressions.
• Generalize a process for finding the percentage that C is of B and justify (orally) why this can be abstracted as $\frac{C}{B} \boldcdot 100$.

### Student Facing

Let’s find percentages in general.

### Student Facing

• I can solve different problems like “60 is what percentage of 40?” by dividing and multiplying.

### Glossary Entries

• percent

The word percent means “for each 100.” The symbol for percent is %.

For example, a quarter is worth 25 cents, and a dollar is worth 100 cents. We can say that a quarter is worth 25% of a dollar.

• percentage

A percentage is a rate per 100.

For example, a fish tank can hold 36 liters. Right now there is 27 liters of water in the tank. The percentage of the tank that is full is 75%.