I don't understand these types of problems ... On a test with 25 problems, Grace got 88% correct. How many problems did Grace get correct?

25 problems = 100%

Anytime you have to find a percent of something, just take whatever 100% is and multiple it by the decimal form of the percent (hopefully that makes sense)

To find out what 88% of the problems are, you would multiple 25 x. 88. The answer would be 22.

Its easy, see

Number of problems = 25

Percentage correct = 88%

Therefore, number of problems correct = 88% of 25

88/100 * 25 = 22

Just remember, when percentage comes take it upon hundred and multiply by the total number given.