1. Two fifths of the 90 students were males. How many students were male?

36

Step-by-step explanation:

Divide 90 by 5 so that you will have groups of fifths. Each fifth of the 90 students contains 19 students. Since you need to know how many male students were in two-fifths of the students, add 19 + 19. You will get 36, your answer.

Another way you could do this is by multiplying 90 by 2/5.

associative property of multiplication