Among the numbers 1, 2, 3, ..., 1000, how many numbers are multiples of 5 or multiples of 7?
+128406 Number of integers divisible by 5 from 1 to 1000 = 1000 / 5 = 200
Number of integers divisible by 7 from 1 to 1000 = integer part (1000/7) = 142
But we must subtract out those integers which are multiples of 5 and 7, ie., all the multiples of 35
So integer part (1000/35) = 28
So ....number of integers that are multiples of 5 or 7 = 200 + 142 - 28 = 314
