If all multiples of 3 and all multiples of 4 are removed from the list of whole numbers 1 through 100, then how many whole numbers are left?

1-100

100/3 = 33

100-33 =67

100/4 = 25 BUT ...some of those are multiples of 3 12 24 36 48 60 72 84 96 and have already been counted as multiples of 3

so instead of 25 it is 25 - 8 = 17

33+17 = 50

100-50 = 50 numbers left

Multiples of 3: 100/3= 33 1/3 - 33

Multiples of 4- 25, some are multiples of 3, so 25-8=17, so 33+17=50