Percentage is one way of measuring the part of a whole, just like fractions or decimals. The word “percent” really means “per hundred”. For example, 20 percent (or 20%) is the same as saying 20 per hundred, or 20/100. If you had a pizza cut into 100 slices, 20% of that pizza would be 20 slices! For more information on percentage, check out our Percent lessons.