# Lesson 12

Meaning of Exponents

### Lesson Narrative

In their prior work with area and volume, students encountered expressions in which a number was squared or cubed. This lesson extends that work by considering exponent notation for any positive whole number exponent. In the warm-up, students first consider a dot pattern where the number of dots is repeatedly multiplied by 3 in each successive level. They next consider a situation involving money that repeatedly doubles, and engage in MP8 by connecting the repeated calculations to expressions involving exponents. Students then make use of the new shorthand notation to write expressions with exponents that evaluate to a given number.

### Learning Goals

Teacher Facing

• Describe (orally and in writing) a pattern that could be expressed using repeated multiplication.
• Generate and evaluate numerical expressions involving whole-number exponents.
• Interpret expressions with exponents larger than 3, and comprehend the phrase “to the power” or “to the” (in spoken language).

### Student Facing

Let’s see how exponents show repeated multiplication.

### Student Facing

• I can evaluate expressions with exponents and write expressions with exponents that are equal to a given number.
• I understand the meaning of an expression with an exponent like $3^5$.