[[Mathematics]] Percents are just that... percents. Of a whole number, they are a number over 100. So 30/100 is 30% 100% is equal to 1. Some people say 100% increase, which means that you start at one, and add another 100%, so it's actually the value multiplied by 2, which is 200%. ## Estimation Methods * By Tens: 20% of 80 is 2 x 8 = 16. Therefore, you can estimate 24% of 60 by simply doing 2 x 6 = 12, and then adding a little bit as you feel. * Percents are invertible, so 20% of 50 is the same as 50% of 20, which is 10. --- # References