Answer:
See photo.
Explanation:
First, you need to find an already complete row, column, or diagonal and find its sum. This is the value that every other row, column, and diagonal needs to add up to. Next, find one that has two values filled in. Add these two numbers. Subtract them from the sum. The number you get is what needs to be in open box of that row/column/diagonal. Then you'll have another with two values, and you do the same thing for that one, and continue.
Example: 0+7+2= 9 so the sum for the left one is 9. you have a column with a 7 and a 3. 7+3= 10. 9-10= -1. then look at the diagonal. you have 2 and 3. 2+3=5, 9-5=4 so 4 is that one. and so on.