Multiply the number by 100 and put a percentage sign after it. If the number is bigger than 1 you get a large number. So 1 is 100%. Most percentages are the result of converting fractions, so think of the fraction of a hundred. You multiply the fraction by 100, since that's what "of" means. Take 1/2, for example, that's half of a hundred=50%. Some fractions don't give exact answers: a third of a hundred is approximately 33%. To convert the other way, convert percentages to fractions, you divide by 100, so 20% is 20/100=1/5, a fifth.