Answer:
Explanation:
I used to do these as a kid! theyre pretty fun :)
for the first one:
the sum has to be 9. (as we can see from the first row).
the middle box in the last row will be -1. (since two boxes fill to be 10, you subtract 1 to get to 9)
and so on. it solves itself. use similar tactics for all others.
1:
0 7 2
5 3 1
4 -1 6
2:
1 2 6
8 3 -2
0 4 5
3:
3 -2 5
4 2 0
-1 6 1