A, B, C, D, E, F, G, H, I are one of integers of 1～9, respectively.
When A + B = C，B + D = E，E × F =C，and D × D = G, find H + I.
Answer
11
Solution
According to D × D = G, D = 2, G = 4 or D = 3, G = 9.
In case D = 2, G = 4, 0 ≦ E.
According to E × F = C, F ≠ 1.
If E = 3, 5 ≦ F then 15 ≦ C, which is not suitable.
Even if E = 5, 6, 7, 8, 9, then 15 ≦ C, which are not suitable as well.
Thus D = 2, G = 4 is not suitable.
In case D = 3, G = 9, 4 ≦ E.
According to E × F = C, F ≠ 1.
If 5 ≦ E, 10 ≦ C.
Thus E should be 4.
Then according to E × F = C, F should be 2 and C should be 8.
According to B + 3 = 4, B = 1 and A = 7 as A + 1 = 8.
There remained 5 and 6 which are H or I.
Therefore H + I = 11.
When A + B = C，B + D = E，E × F =C，and D × D = G, find H + I.
Answer
11
Solution
According to D × D = G, D = 2, G = 4 or D = 3, G = 9.
In case D = 2, G = 4, 0 ≦ E.
According to E × F = C, F ≠ 1.
If E = 3, 5 ≦ F then 15 ≦ C, which is not suitable.
Even if E = 5, 6, 7, 8, 9, then 15 ≦ C, which are not suitable as well.
Thus D = 2, G = 4 is not suitable.
In case D = 3, G = 9, 4 ≦ E.
According to E × F = C, F ≠ 1.
If 5 ≦ E, 10 ≦ C.
Thus E should be 4.
Then according to E × F = C, F should be 2 and C should be 8.
According to B + 3 = 4, B = 1 and A = 7 as A + 1 = 8.
There remained 5 and 6 which are H or I.
Therefore H + I = 11.
