Posted by
**Tim** on
.

My teacher gave us a puzzle.

I have worked on it for 2 hours with both my parents and they can not figure it out.

0 o 0

o 0 o

0 o 0

In the above there are 5 squares. Top left, top right, bottom left and bottom right, and the last one formed by the o's diagaonally.

Arrange numbers 1 to 9 so that the sum is 20 in each square. We can get 4 of them done. But nothing more.