Here's a sample SAT problem that uses the concept of exponents.

2^x + 2^x + 2^x + 2^x  = 2^7.  What does x equal?

It's temping to say 7/4 because 2^x appears 4 times and 7/4 times 4 = 7. But that isn't correct.

You need to calculate 2^7 first, which is 128.

Now since 2^x is added to itself 4 times, you can rewrite the equation as

4(x^2) = 128

Therefore, dividing by 4 gives x^2 = 32. 

The value of x is five since 2 * 2 * 2 * 2 * 2 = 32