Computing percents mentally

To find the percent of a number easily you may use the fraction equivalents of percents. For example, 50% of 120 is the same as 1/2 of 120 or 60. You may also use 10% of that number to find other percentages. For example, to find 65% of 120 you may find 10% first. 10% of a number means that you divide that number into 10 equal parts, so 10% of 120 is 12. To get 60% of 120 you need 6 times more than the 10% that you have. Therefore, 60% of 120 is 12 times 6 or 78. To get the remaining 5% remember that 5% is half of 10%, so 5% of 120 is 6. To get 65% add what you have for 60% and 5%. The value that you get is 84. Please review the previous posts to see a video example of how to do this.


The homework for tonight is pg 270 numbers 8-25,36,37.