How to Solve Cryptarithms

Cryptarithms are easiest when you treat them as a chain of small arithmetic constraints rather than one giant guessing problem.

1. Work column by column

Start with the rightmost column. Write down what the units digits can be and whether that column creates a carry into the next column.

2. Track carries explicitly

A carry is usually 0 or 1 in two-number addition. Knowing the carry often eliminates several possible digits immediately.

3. Protect leading digits

The first letter of a multi-digit word cannot be zero. This simple rule often removes otherwise plausible assignments.

4. Reuse every deduction

When a letter is fixed, apply that digit everywhere the same letter appears. Cryptarithms become much easier once information is propagated across columns.

5. Use contradictions

If one assumption forces two different letters to use the same digit, creates an impossible carry, or breaks the equation, reject that branch.

For practice, try Cipherix, a mobile game built around these deduction techniques.