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1.02 Evaluate exponents

Introduction

We have previously looked at  exponents  and how they can be written in exponential form, a^{b}, or expanded form, a \times a \times a..., as a product of factors. Now let's look at how to evaluate or simplify problems involving exponents.

Evaluating exponential expressions

A base to the power of any other number, e.g. 3^4, can be read as "3 to the power of 4", and means that the base number is multiplied by itself the number of times shown in the power.

3^4=3\times3\times3\times3

To evaluate or simplify the above exponential expression, the only step we need to take is completing the multiplication. The simplified product is the number in standard form.

\displaystyle 3^4\displaystyle =\displaystyle 3\times3\times3\times3
\displaystyle =\displaystyle 81Simplify the multiplication

The exponential expression 3^4 is evaluated to 81, the number in standard form.

Examples

Example 1

Evaluate 3^2.

Worked Solution
Create a strategy

Write the expression in expanded notation.

Apply the idea
\displaystyle 3^2\displaystyle =\displaystyle 3 \times3 Multiply 3 by itself two times
\displaystyle =\displaystyle 9Evaluate

Example 2

Evaluate \left(\dfrac{2}{5}\right)^4.

Worked Solution
Create a strategy

Write the exponential expression in expanded form and perform multiplication.

Apply the idea
\displaystyle \left(\dfrac{2}{5}\right)^4\displaystyle =\displaystyle \dfrac{2}{5} \times \dfrac{2}{5} \times \dfrac{2}{5} \times \dfrac{2}{5} Multiply \dfrac{2}{5} by itself four times
\displaystyle =\displaystyle \dfrac{16}{625} Evaluate multiplication of numerator and then the denominator
Reflect and check

How would you evaluate an exponential expression with a decimal base?

Idea summary

An exponent or power tells how many times a base number must be multiplied by itself.

To evaluate an exponential expression, expand the notation and perform the multiplication.

Outcomes

6.EE.A.1

Write and evaluate numerical expressions involving whole-number exponents.

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