Here's a good sample SAT math problem.

Suppose a and b are real numbers and (a + b)^2 = 56 and a^2 + b^2 = 18. What is the value of  ab?

The key to the problem is knowing that when you expand (a + b)^2, you will have a^2 + b^2 and ab as part of the expansion, which makes the problem easy.

(a + b)^2 = a^2 + 2ab + b^2

Now substitute and solve for ab.

56 = 18  + 2

38 = 2ab

19 = ab