In Games and warm-ups, Number and Algebra, Whole Numbers

Learning Objective:
Name multi-digit numbers, use previous information to solve problems.

Intended Outcome:
Using previous information to eliminate digit possibilities.


  • Whiteboard
  • Pen and paper

Game Objective:
To guess the mystery number.

This game is to be played as a whole class, in small groups or in pairs.

  1. The ‘caller’ decides a mystery number. Four or more digits is best.
    Hint: Write the mystery number down; relying on memory is hard.
  2. A player guesses the number and the guess is written on the board.
    Hint: It is a good idea for the teacher to do the writing as it makes it faster.
  3. The caller marks each digit of the number with a tick if it is correct, a circle if it is in the mystery number but not in the correct place, and a cross if it is not in the number at all.
  4. Players continue guessing and the caller continues marking each digit in each number, until the correct number is discovered.
  5. Ensure the students name the number correctly aloud, e.g. Forty-three thousand, seven hundred and eighty-six.

Hidden mystery number: 49273

First guess:
4 3 7 8 6
✓ o o x x

Second guess:
4 1 9 3 2
✓ x o o o

Third guess:
4 9 2 3 5
✓✓✓ o x

Fourth guess:
4 9 2 7 3

Try using decimals in the mystery number.

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