how many integers from 1 to 2009 are divisible by 5, or by 7, or by 9? how many integers from 1 to 2009 are divisible by 5, or by 7, or by 9? @Mathematics

Question

how many integers from 1 to 2009 are divisible by 5, or by 7, or by 9?  how many integers from 1 to 2009 are divisible by 5, or by 7, or by 9?  @Mathematics

anonymous · Answer

401, 287 and 223 respectively

anonymous · Answer

thank you
if this were to be a set theory problem, what would be the union?

mathteacher1729 · Answer

How did you obtain those numbers moorsy?

anonymous · Answer

2009/5, 2009/7, 2009/9... all rounded down as needed

anonymous · Answer

dividing by 5 would give you 401 numbers
dividing by 7 would give you 287 and by 9 would give 223 like moorsy says

mathteacher1729 · Answer

That is an elegant solution. :) I was going to try to write a little snippet of code to count up the divisors from scratch. :-p