To make a percentage into a fraction you divide it by 100. This means 12.5% is 12.5/100. However, when giving fractions as an answer it needs to be done in the simplest form. To do this you need to find the highest common factor. This means you need to find the biggest number that can multiply with another whole number in order to produce 12.5 and 100. The whole number to produce 12.5 and 100 can be different. In this case the highest common factor is 12.5 as 12.5 times 1 is 12.5 and 12.5 times 8 is 100. Now you divide the top and bottom of the fraction by 12.5 to produce 1/8.