## 4 Common Errors in Calculating Expressions with Exponents

The errors below are usually made by students in calculating algebraic expressions with integer exponents. These errors result from the misunderstanding of the law of exponents.

If you have seen  errors like the following, please don’t hesitate to use the comment box below.

Common Error 1$-a^n = (-a)^n$

That equation is only true if $n$ is odd. If $n$ is even, the equation does not hold. For example, in the expression $-3^4$, the exponent $4$ only applies to $3$ and not $-3$. That means that $-3^4 = - 81$. However, $(-3)^4 = 81$» Read more