Imagine you have a 5 x 5 grid. You have to place the numbers 1-25 on the grid so that each row, columnanddiagonal add up the the same number, can it be done?

For example, here's what I mean with a 3x3 version.

4 9 2

3 5 7

8 1 6

All columns, rows and diagonals all add up to 15.

I would love someone to work this out, been annoying me for ages.