when u think of multiples...think of multiplication tables...
5 x 1 = 5
5 x 2 = 10
5 x 3 = 15
and so on.....so ur multiples of 5 are 5,10,15..and so on
so multiples of 5 starting at 75 would be.....75,80,85,90,95,100...and so on....not sure how far ur supposed to count to...