Percentage is only a way of representing a fraction or mixed number, because "per cent" means "by 100". So 27% is 27/100. 100% means 1; 150% means 1 1/2 or 1.5. If you're used to dollars or pounds and cents or pence, think of 1 cent or 1p as representing 1% of a dollar or pound. 50 cents or 50p is half a dollar or pound and it's 50%. 25 cents is a quarter (of a dollar) and 25% actually means 1/4. Get the idea?