A certain kind of stapler holds 210 staples when fully loaded. A box of staples for this kind of stapler contains 5,000 staples. If you use a full box of staples and fully load as many empty staplers as possible, how many staples will be left in the box?

This is simple, just divide 5,000 by 210

5000 : 210 = 23.809

23.809 = 23.81

23.81 = 23.8

23.8 = 23

Thats for staplers being full, now for how many is left

It would be 170, for that, you have to subtract:

5000 - (210 · 23) = 170

5000 - 4830 = 170

170

Your answer would be:

23 staplers would be full and 170 staples were left