Multiple choice general knowledge math & puzzles

Odd one out 213 111 121 222 333 201 303

  1. 303

  2. 213

  3. 201

  4. 121

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In the set, all numbers except 121 have a digit sum that is a multiple of 3 or follow a specific pattern of external digits summing to the middle (except 121 is a perfect square). More simply, 121 is the only perfect square (11^2) in the list.