One of the thins I've learned for myself (through sad experience) is that success in math demands practice. You think you understand the material until you hit a problem you can't solve; panic ensues, you stop, and the result is that you're upset and you've learned nothing. Neither is a good outcome.
If you can't solve a problem, see if you can make up a simpler version of the same problem, and solve that.
If it's statistics, make up a small data set -- the numbers 1-10 if all else faild, snad work the problem with that. This will often make teh method clear, and you can go back to the data set in the problem.
For fractions (amazing how many students haven't mastered them) make up numers like 83/26 and 38/81, and try adding, subtracting, multiplying, and dividing them. Have someone else check the answers.
The more you do, the more you understand, and at some magical point, solving the problems will be alnost automatic.