Negative Exponents Explained
A negative exponent tells you to move the base across the fraction bar. Once the base moves, the exponent becomes positive. Although negative exponents can look confusing at first, they follow a simple movement rule that makes rewriting expressions much easier.
How It Works
Find the negative exponent
Look for the exponent with a minus sign. This tells you which number needs to move.
$$2^{-3}$$
Move the base to the other side of the fraction
The number with the negative exponent moves across the fraction bar.
$$2^{-3}=\frac{1}{2^3}$$
Make the exponent positive
Once the base moves, the exponent becomes positive automatically.
This works the same way even if the negative exponent starts in the denominator.
$$\frac{1}{7^{-2}}=7^2$$
Try These Examples
Rewrite the expression using positive exponents: $$4^{-1}$$ $$
The base moves to the denominator and the exponent becomes positive. Rewrite the expression: $$\frac{1}{7^{-2}}$$ $$7^2$$
Because the negative exponent is in the denominator, the base moves to the numerator.
\frac{1}{4}
$$
Watch Out
Common Mistake
A negative exponent does not make the value negative.
The negative sign tells you to move the base across the fraction bar, not to change its sign.
$$
2^{-3} = \frac{1}{8}
$$
$$
2^{-3} \neq -8
$$
A negative exponent does not make the value negative.
The negative sign tells you to move the base across the fraction bar, not to change its sign.
$$
2^{-3} = \frac{1}{8}
$$
$$
2^{-3} \neq -8
$$
Keep Practicing
Try these related worksheets to build fluency and confidence.