Now hear this. Don't take any shortcuts. If you don't succeed, spend 5 minutes analyzing exactly what it was about each problem that you didn't understand. You have all the tools at your fingertips, you are afraid to use them. Remember testing strategy.
Some problems are easy and take very little time.
Do those first since you have a high rate of return on points per test time invested. Keep your working neat as you are working the problems. Panic scribbles on an exam indicate that you haven't mastered the information. You have plenty of time on every problem to set it up in an organized way on your exam sheet. The actual calculations normally take about 30-45 seconds.