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.
6 = 1 + 5 7 = 3 + 4 9 = 2 + 7 16 = 6 + 10 17 = 8 + 9
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.
There are four solutions.