I've got:
Divisible by... 2, 3, 5, 2 and 3, 2 and 5, 3 and 5
No of integers 3000, 2000, 1200, 1000, 600, 400
And then it's
6000
- 3000 (integers divisible by 2)
- 2000 + 1000 (integers divisible by 3 but not 2)
- 1200 + 600 + 400 (integers divisible by 5 alone)
= 1800
Is this right? Can anyone think of any better ways of doing it?