nerdle

Nerdle #121 Answer

Friday, May 20, 2022

99*4=396
Structure
AB*C=DEF
Type
Mixed-Length Multiplication
Result
396

How the clues would have read

  • Today's equation begins with a two-digit number in the 90s.
  • This puzzle uses multiplication only.
  • The result is a 3-digit even number.

The numbers behind it

  • Divisibility: 99 is divisible by 3, 9, 11, and 33, 4 is divisible by 2, and 396 is divisible by 2, 3, 4, 6, 9, 11, 12, 18, 22, 33, 36, 44, 66, 99, 132, and 198
  • Digital roots: 99 → 9+9 = 18 → 9, 4 → 4, 396 → 3+9+6 = 18 → 9
  • Prime factorization: 99 = 3²×11, 4 = 2², 396 = 2²×3²×11

Why the structure matters

This puzzle's shape is AB*C=DEF — a mixed-length multiplication, where each letter stands for one digit. Recognising the shape before the arithmetic is what separates a three-guess solve from a six-guess struggle: once you know the equation is a mixed-length multiplication, most of the search space is gone before you have spent a single guess.

The result, 396, factors as 2²×3²×11 — those factors are exactly the operations that could have produced it.

Nerdle is made by Nerdle Limited. nerdle.vip is an independent fan site and is not affiliated with or endorsed by them. Puzzle numbers and answers on this page refer to the official game at nerdlegame.com.