100 of them
100
99 / 3 = 33 threes 100/3 = 33.33 threes which rounded would be equal to 33 threes
33.33... the threes never will end.
3 goes into 300 100 times.
35
210
There are 9 threes in 28... with a remainder of 1 !
22
They don't. Five threes add up to 15 and that is it! You can write an expression using 5 threes that makes 100, but that is not the same.
300
27 threes are in 81