You do not need algebra and calculus. You don't need geometry or trigonometry. You don't even need long division (or if you do need it, you certainly don't need to do it by hand). You need addition, subtraction, multiplication, and simple division. You can use a calculator. But it's also helpful to have some of these sums and products at your fingertips so that if you're in a store, for instance, and you want to know what it will cost you to buy seven turtlenecks for your kids at \$12 apiece, you can do the math in your head.
You also need a basic grasp of percentages, decimals, and fractions. If you feel you need some help boning up on these skills, I've provided a basic primer below.

Percentages
What are they? The word percent means "parts of 100." If someone says you scored a 70 on a 100-item math test, that means you got 70 out of 100 correct and achieved a 70 percent success rate.

Real Life, Real Money Use
Interest rates, inflation rates, tips in restaurants, and how much interest you're earning on your money are expressed as percentages. You can use them to compare the deals you get on money market accounts from various banks. If one bank is offering 2 percent annually and another is offering 3 or 4 percent, you can easily tell where you'll be getting the better deal.

Math 101 continues...