2 Similar questions:

I. Difference

Arrange numbers 1 to 8 to replace the letters so:
A = abs (abs BB – D)
C = abs (abs BB – E)
F = abs (abs DD – G)
H = abs (abs EE – G)
To eliminate duplicates by rotation and reflection, let’s set the rules: A > C, A > F, A > H and F > C
There are 2 solutions

II. Addition

Arrange numbers 1 to 8 to replace the letters so:
A = B + D
C = B + E
F = D + G
H = E + G
To eliminate duplicates by rotation and reflection, let’s set the rules: A > C, A > F, A > H and F > C.
There is just 1 solution