How to play Guess My Number
- Choose the biggest number it could be.
- Ask a question, such as “Is it bigger than 50?” or “Is it a multiple of 3?”
- Watch the number of possible answers drop.
- When you think you know, type your guess.
Maths skills this game builds
- Number properties: odd, even, prime, square, multiples
- Logical thinking and reasoning
- Halving and binary search idea
- Asking good questions
Tips for parents and carers
- The best question splits the possibilities in half. Try “Is it bigger than 50?” first.
- Play the real-life version with a secret number in a notebook.
- Ask “How many questions do you think you need?”
Using Guess My Number with a group or class
- Groups take turns choosing the next question. Discuss why one question is better than another.
- Use 1 to 20 for younger children and 1 to 1000 as a stretch.
- Challenge: can you find any number from 1 to 100 in seven questions?
Frequently asked questions
What is the best strategy?
Ask questions that cut the possibilities in half, such as “Is it bigger than 50?”.
How many questions will I need?
Any number from 1 to 100 can be found in 7 questions if you always halve.
Can I use my own questions?
You can choose from the question types on the page.