7th Grade Math

Monomials

PART B CDE

4

Multi-Part Lesson

Get ConnectED

A

GLE 0706.2.6 Introduce the concept of negative exponents. SPI 0706.2.1 Simplify numerical expressions involving rational numbers.

Negative Exponents

Copy the table at the right.

Power Value 26 64 25 32 24 16 23 8 22 4 21 2

(^20)
2 -^1

Describe the pattern of the powers in the first
column. Continue the pattern by writing the
next two values in the table.

Describe the pattern of values in the second
column. Then complete the second column.

Determine how 3-^1 should be defined.

Negative Exponent

Words Any nonzero number to the negative n power is the multiplicative inverse of its nth power. Symbols a-n = _a^1 n , for a ≠ 0 and any integer n

Example 5 -^4 = _^1 54

Use Positive Exponents

Write each expression using a positive exponent. 6 -^2 6 -^2 = _^1 62

x-^5 x-^5 = _^1 x^5

Definition of negative exponent

a. 5 -^6 b. t-^4

Use Negative Exponents

Write each expression using a negative exponent other than -1. _^1 9 = _^1 32

Definition of exponent

= 3 -^2 Definition of negative exponent

_^1 d^5

= __^1 d · d · d · d · d Definition of exponent

= d-^5 Definition of negative exponent

c. _ 161 d. _^1 t^6

Main Idea Write expressions using negative exponents.

Vocabulary negative exponent

Lesson 4B Monomials 181

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176_189_C3L4_895130.indd 181 12/31/09 12:50 PM