Four Digit Code Breaker

What you need

• Paper, 2 sheets, plus extra for more rounds
• Crayons or markers, 2 pencils (or markers)

How to do it

Grown-up prep: Give each player a sheet of paper and a pencil. Check that everyone knows what a hit and a near miss are before you start. The clue words are explained in the step details.

1. Draw a table with three columns: Guess, Right spot, and Wrong spot.
2. Code maker: secretly write a four digit code and hide it.
3. Code breaker: guess any four digit number and say it out loud.
   Ask: Which digits do you think might be in the code, and why?
4. Code maker: say how many digits are the right number in the right spot.
5. Then say how many are the right number in the wrong spot.
6. Write down the score, then use logic to work out your next guess.
   Ask: What can you rule out now that you know these clues?
7. Keep guessing until you crack the code, then count your guesses.
8. Swap roles and play best of three! Who can crack it in fewer guesses?
   Ask: What clever trick helped you most, and will you use it next time?

Play it again

• Team up: two people work together as the code breaker against one code maker.
• Speed round: set a two minute timer and see how far you get.
• Zero rule: allow the code to start with 0 and see how it changes your guesses.