Exercise 41 Page 142

To mentally calculate what percent of a number a given value is, we can divide this value by the original number and then multiply by 100. To calculate what percent of 40 30 is, we can divide 30 by 40.

30÷40=0.75 Now, if we multiply this result by 100, we will get the percentage of the original number. 0.75*100=75 % Therefore, 30 is 75 % of 40.