SUBTRACTION
A=7
B=1
C=4
D=8
E=5
F=6
G=2
H=3
A>C
A>F
A>H
F>C
METHOD
I tried to get the higher values inside the result box. I chose 7 out of 7 and 8. And then, got the following things working -
8-1 = 7
8-2 = 6(Next big number)
5-1 = 4(Next big number)
5-2 = 3(Final big number)
ADDITION
A=8
B=2
C=5
D=6
E=3
F=7
G=1
H=4
A>C
A>F
A>H
F>C
METHOD
For addition, I tried getting the bigger numbers in the result box.
6+2 = 8(Biggest)
6+1 = 7(Next biggest)
3+2 = 5(Next biggest)
3+1 = 4(Final)