You might not have learned about percentages in school yet, but people use them all the time. Have you heard the phrase “splitting something 50/50”? Both of those 50s are percentages. A percentage is a way to tell us how much of something there is.
Almost always, when you see “cent” in a word, it has something to do with the number 100. A penny is sometimes called a cent, and 100 cents add up to one whole dollar. 100 centimeters add up to one whole meter.
When we talk about a percentage, we imagine what it would be like if a whole object was broken up into 100 equal pieces. Each of those pieces is one percent. If you think of a pizza cut up into 100 slices that are the same size, each time you ate a slice, you would eat one percent (1%) of the pizza. If you ate fifty slices, you would eat fifty percent (50%) of the pizza, which is the same as saying “one half.”
It may seem like percentages just make things more difficult, and sometimes that is true. Most of the time they are really helpful. Most quizzes you take in school will be graded with percentages. If you got a 100% on a quiz, you got everything correct. If you got an 80% on a quiz, it means your teacher did some math to figure out your grade. The total of all the right answers was broken down into 100 equal pieces, and you got eighty of those correct (80%). If there were only 5 questions on the test, it means you got 4 correct. If there were 10 questions on the test, you got 8 correct.
If you want some more examples of percentages, ask a grownup about taxes and tips.

Further information
%
When you see this symbol, it means “percent.” 14% means “fourteen percent.”

Exploration
Coin Counting
Each of the coins that we use as money in the United States is worth a certain percentage of a whole dollar.
A penny is equal to one cent. It is 1% of a dollar.
A nickel is five cents, or 5% of a dollar.
How much is a dime worth? What percentage of a dollar does that equal? How many dimes will it take to make a whole dollar?
How about quarters?
If you have trouble with the math, ask a grownup for help. You might be a couple years away from learning this in school.