Name multi-digit numbers, use previous information to solve problems.
Using previous information to eliminate digit possibilities.
- Pen and paper
To guess the mystery number.
This game is to be played as a whole class, in small groups or in pairs.
- The ‘caller’ decides a mystery number. Four or more digits is best.
Hint: Write the mystery number down; relying on memory is hard.
- 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.
- 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.
- Players continue guessing and the caller continues marking each digit in each number, until the correct number is discovered.
- Ensure the students name the number correctly aloud, e.g. Forty-three thousand, seven hundred and eighty-six.
Hidden mystery number: 49273
4 3 7 8 6
✓ o o x x
4 1 9 3 2
✓ x o o o
4 9 2 3 5
✓✓✓ o x
4 9 2 7 3
Try using decimals in the mystery number.