10 + 2 = 12 9 + 3 = 12 8 + 4 = 12 7 + 5 = 12 1 + 6 = 7

Using all the numbers from 1 to 10, put them into pairs, so that one pair adds to 6, another pair to 7, a third pair to 9, a fourth pair to 16 and the final pair add to 17.

Can you arrange the numbers from 1 to 9 on a tic tac toe board in a manner that the numbers in each row, column and diagonal adds up to 15. Remember that you have to use all the 9 numbers and thus you cannot repeat.