Cryptarithmetic

SEND + MORE = MONEY is the most famous cryptarithmetic puzzle, first popularized by the English mathematician Henry Dudeney in 1914. In this puzzle, each letter represents a unique digit from 0 to 9, and solvers must find the specific digit-to-letter mapping that makes the arithmetic equation true.

To solve a cryptarithmetic puzzle, you must use deductive logic and arithmetic constraints to assign digits to letters, ensuring no two letters share the same digit. Solvers typically look at the carry-overs in column addition and rule out impossible number combinations.

The primary rules of cryptarithmetic are that each distinct letter must represent a distinct digit, and numbers cannot have leading zeros. The arithmetic equation must also form a valid mathematical statement once all letters are correctly replaced by their corresponding digits.

While puzzles involving words and numbers existed earlier, Henry Dudeney is credited with popularizing cryptarithmetic with his classic 1914 SEND + MORE = MONEY puzzle. His puzzle appeared in the Strand Magazine and set the standard for the genre.