A four digit code has to be entered into this keypad to open the door to a safe. There are four rules: • The code must be an even number • There must be at least one digit from each row • There must be at least one digit from each column • When you add the digits together it makes an even number Which code is correct?
Sign in or create an account to reveal answers, view the solution, and save your progress. Create a free account to unlock practice and keep track of your work.
First Mathematics Challenge (2023)
One puzzle per day. Cryptarithm, Magic Square, Summit. No sign-up required to play.
Play daily puzzle →Interactive problems and curated lessons—water pouring, magic squares, knight's tour, and more.
Browse library →See how you rank. Top solvers by problems solved correctly. Sign in to climb the ranks.
View leaderboard →First Mathematics Challenge (2023)