Bobthebandit, take, for example, 20%. That means 20 over 100 as a fraction. Next you think of a number that divides evenly into BOTH 20 and 100. You might pick 2, so 2 into 20 goes 5 times, and 2 into 100 goes 50 times, So, that gives you a new fraction: 5 over 50. But wait a minute, you think, 5 and 50 can BOTH be divided by 5. So five goes into five 1 time, and 5 goes into 50 10 times. therefore you end up with 1/10. Your question about 13% means 13 over 100, and there is no number that divides evenly into BOTH 13 and 100; therefore, 13% is simple 13/100.