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