How many positive integers between 100 and 999 inclusive are multiples of 5? Are multiples of 3 but not 5?

There are 999−100+1 = 900 numbers between 100 and 999 inclusive

1/5 th of them are multiples of 5

900/5 = 180

180 are multiples of 5

——————————————————————————————

900/3 = 300

900/15 = 60

240 are multiples of 3 but not multiples of 5

plainly, there are 20 multiples of five in each hundred integers. since your range is 900 integers long, there, therefore, are 180 of them. [note that 900 divided by 5 is 180]

for the second part, divide 900 by 3 and then subtract the occurrences of 15, using the method outlined to figure out how many there are

What a stupid question. I love math. but that serves no purpose. Tell your teach to blow me