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Understanding Exponents

A Shorthand for Multiplication

Imagine you need to multiply a number by itself over and over again. Writing out 4×4×4×4×44 \times 4 \times 4 \times 4 \times 4 is a bit tedious. Mathematicians love shortcuts, so they came up with a cleaner way to write this: exponents.

454^5

This little expression means the exact same thing as the long multiplication problem above. It's just a compact way of saying "multiply 4 by itself 5 times." This notation has two key parts: the base and the exponent.

Base

noun

The number being multiplied by itself.

Exponent

noun

The small, raised number that tells you how many times to multiply the base by itself.

Evaluating Expressions

When you see an expression with an exponent, you'll often need to "evaluate" it. That's just a fancy way of saying you should do the multiplication to find the final value.

To evaluate an expression, you write out the base the number of times the exponent tells you to, and then multiply.

Let's try our first example, $4^5$.

45=4×4×4×4×4=10244^5 = 4 \times 4 \times 4 \times 4 \times 4 = 1024

Here are a few more. Notice how the value can grow very quickly.

For $2^3$, the base is 2 and the exponent is 3.

23=2×2×2=82^3 = 2 \times 2 \times 2 = 8

For $5^2$, the base is 5 and the exponent is 2. This is often read as "five squared."

52=5×5=255^2 = 5 \times 5 = 25

A common mistake is to multiply the base and the exponent together. For example, it's easy to think 232^3 equals 2×32 \times 3, which is 6. But as we saw, the real answer is 8. Always remember that the exponent tells you about repeated multiplication, not a single multiplication.

Let's check your understanding of these new concepts.

Quiz Questions 1/5

In the expression 838^3, what is the number 3 called?

Quiz Questions 2/5

Which expression is equivalent to 4×4×4×4×44 \times 4 \times 4 \times 4 \times 4?

Exponents are a fundamental building block in algebra and beyond. Getting comfortable with what they mean and how to evaluate them will set you up for success as you tackle more complex ideas.