20 percent of 30 dollars is 6 dollars.

If an item costs 30 dollars and it's on sale for 20 percent off, how much will you save? To figure this out, you need to find 20 percent of 30.

This is easy to do in your head. Think of what 10 percent would be. 10 percent of 30 would be the same as .10 x 30, or 3. So, 10 percent off is 3 dollars off.

20 percent is twice as much as 10 percent. If 10 percent off is 3 dollars, then 20 percent off would be 2 x 3 or 6.

20 percent of 30 dollars would be 6 dollars.