• B + C = A
• B + D = C

• B = CC

• B + D = A + 2
• A + D = B + 4

• B + D = A + 4
• B + C = D + 3

• C = D + 2
• A = D + 1
• A = B + 2

• A = D + 1
• D = C + 2

• B = 4D
• A = 3D

• 2C = B
• 4D = 3B

• 2C = B
• A > B
• 2A = 3B

• 4A = 3B
• 2B = 4D

• B + D = A + C
• D ≠ 2
• A ≠ 4
• C ≠ 4
• A ≠ 3
• B ≠ 4

• C + D = A + B
• D ≠ 2
• A ≠ 2
• C ≠ 2
• D ≠ 4

• 2C = A + D
• B > C
• 2A = B + C

• 2B = C + D
• B > A
• 2C = A + B

• A + C ≤ 3
• C + D = B

• B + D = C
• B + C ≤ 5
• C > A

• A + C = 3
• A + B = 6

• A + C = 6
• A + B + D = 8
• A + B = 5

• if A + D ≤ 6 then B < 1
• if C ≤ 2 then A + B ≤ 4

• if B ≤ 3 then C ≤ 2
• if D ≠ 1 then A + B ≤ 4
• if A + D ≤ 5 then B < 2

• C + D ≤ 6 if and only if A > 1
• D < 1 if and only if B ≤ 2
• D ≠ 4 if and only if A ≤ 3
• A + D ≤ 3 if and only if B ≠ 3

• A + B ≤ 7 if and only if C + D ≤ 3
• C < 3 if and only if A ≠ 3
• A ≠ 2 if and only if D ≤ 1

• A + B = 5
• C = BC
• B + C = 4

• 2B + C = A

• D = BB
• AC = BC + C

• B > AC
• AA = B

• BC = A + C + D
• 2D < 4

• 2C = B
• B + D > 4C
• 4C = D