### How to play

• The variables represents unique integers ranging from 1 to the number of variables;
• Multiplication is implicit: `AB` means `A` times `B`, or `A * B`;
• Based on the clues (equations and inequations), use the grid to create relations between variables and values:
• Click once on a square to mark that value as false;
• Click twice to assign the chosen value to the variable;
• Click three times to clear the square.
• The color of a clue changes after you assign values to all of its variables:
• GREEN means that the statement is true;
• RED means that the statement is false.
• Click on a clue to mark it as used;
• The game ends when all values are correctly assigned to the variables.

### Tips

• Figuring out which variables can't have the lowest or the highest values is a good starting point, e.g, `A > B` shows that `A ≠ 1`;
• Analyzing the hypothetical equation `C + D = 4`, we can make the following statements:
• `C = 1` and `D = 3` OR `C = 3` and `D = 1`;
• No other variable can be 1 or 3 (see Naked Pairs in our Sudoku Guide).
• Another quick tip: `A = 2B` means that `A` is even;
• Don't be afraid of using pen and paper. Some puzzles might require it.

## Logic Equations by size

• 2C = B
• B + D > 4C
• 4C = D

• 4A = 3B
• 2B = 4D

• C = D + 2
• A = D + 1
• A = B + 2

### 5x5 »

• C + E = A + B
• C + D = B + E
• E ≠ 2
• A ≠ 5
• E ≠ 4

• B + C = A + 4
• B + D = A + 1

• D + E = B
• B + D = A
• A + E ≤ 6
• C + E = A

### 6x6 »

• A + F = E
• B + C = F
• C + D = E
• C + F = D

• 4A = 3D
• 4B = 2D
• D = 4C
• E > F

• D + E = C + F
• B ≠ 2
• D ≠ 6
• B ≠ 1
• B + C = A + F
• D ≠ 4
• B ≠ 5

### 7x7 »

• CD = B
• C + F = B + G
• F > B
• C + F + G = E + 9

• 2F = A + D
• 2E = A + C
• 2E = B + D
• 2A = E + F
• B > E

• A + F = 10
• B + G = 10
• B + C = 7
• B + F = 9
• A + C + E = 10

### 8x8 »

• E + F = C + H
• A + G = C + D
• F + H = B + E
• A ≠ 3
• B + F = C + G
• G ≠ 2
• F ≠ 3
• B ≠ 7
• G ≠ 8
• C ≠ 1
• A ≠ 8

• 4A = 3D
• 4D = 2H
• C > A
• 3H = 4B
• F > G
• H = 4E
• C > B

• C + G + H = 17
• C + G = 14
• A + E + G = 13
• C + F = 11
• C + D + E = 9

### 9x9 »

• 4A = 3G
• 4D = 2H
• C > A
• H = 4F
• 3I = B

• B + C = I
• B + H = G
• H + I = F
• D + G = A
• G + I = E
• B + D = C

• A + I = 5
• F + H = 7
• E + F = 6
• G + I = 6
• B + I = 9
• A + D + F = 13