Answer:
1 8 6
9 4 2
5 3 7
Explanation:
1) When solving problems like this it is best to start with the smallest number. In this case the smallest number was 1, so that was placed in the top left corner.
2) The smallest number must be next to the two largest numbers so, 8 and 9 can be placed on its sides
1 8
9
3) solve for the final spots in the first row and the first column.
Row:
1 + 8 = 9
15 - 9 = 6
Column:
1 + 9 = 10
15 - 10 = 5
So,
1 8 6
9
5
3) Looking at the largest unused number, number 7, we can see that it is too large to go in the second row or the second column. This means it must be placed in the lower right corner
1 8 6
9
5 7
4) At this point you have enough information to solve for the rest of the numbers using simple addition and subtraction