# %Math% – Round 4

‘%’ this sign is called percentage sign, It represents percentage. But what is a percentage? Percentage is a different way to show a number that has divided by 100. That’s my meaning, but I don’t think you could understand that, so i will show you the example:

Ex: A store has 150 cookies, They’ve sold 80 cookies of all the cookies, Find the percentage of the cookies that they’ve sold.

• So now you know how many cookies they have and how many cookies they’ve sold
• Now we have to find the percentage of the cookies that they’ve sold
• So you will take 150 times 80 and divide it by 100

150 x 80 ÷ 100

150 x 80 = 12,000

12,000 ÷ 100 = 120

• The short way of dividing by 100 is counting how many 0 does 100 have, and there are two zeros, so you
• 100 have two 0, our answer is 12,000. So we could just delete the two 00 in 12,000, so now the answer is still 120 but it faster to find.

This strategy could work if there are 0 in the answer(Ex: 12,000), but if there aren’t 0 in the answer(Ex: 1356). So, if we divide the answer by 100, we that 100 have two 00. Now imagine that you have a . at the right side of number 6. So we will move the dot two times to the left because 100 have two 0.