Guess my Number

Mathematical Foundations

Key Skills and Concepts

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Guess my Number: Factors and Multiples

Key Skills and Concepts

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Topics Covered:

Factors and Multiples

Multiplication and Division

Times Tables

Problem Solving

Equipment needed:

A pen and paper to make notes if needed

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Overview:

This is quick and simple game you can play and is great for in the car or while you are out and about. You can use a pen and paper to make notes of your guesses or just try and do the whole thing in your head. It is great for practicing times tables and most importantly helps your child distinguish between factors and multiples.

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Instructions:

Select a number between 1 and 20 (you can go higher for further rounds to make it more challenging).

Your opponents then needs to try and ask questions which must be about factors and multiples to try and work out what your number is in as few a questions/guesses as possible. You can also allow ‘greater than’ or ‘less than’ questions to make it a little easier, but I would limit how many of these you allow so they focus on factors and multiples more.

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Example – Can you work out what number between 1 and 20 I am thinking of in this example game below?

Q1: Is your number a multiple of 2?

A1: No

Q2: Is 3 a factor of your number?

A2: Yes

Q3: Is your number a multiple of 5?

A2: Yes

Q4: Is your number a factor of 20?

A4: No

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Try and encourage your child to alternate between factor and multiple questions so they get used to the two different (yet very connected) terms.

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Key Questions/Prompts:

Can you explain what a multiple is?

Can you explain what a factor is?

(Child: Is your number a multiple of 4?) Can you ask that same thing using a factor question instead of a multiple question?

Which numbers do you think it could be?

Which numbers do you know it can’t be?

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Extension:

You can easily extend the challenge by allowing numbers that are higher than 20. You can also turn it into a race where you both pick a number and take it in turns to ask a question. See who can guess the other person’s number first.

You should also open up the discussion about which numbers are harder to guess. The language of factors is really important in this discussion and can even open up a great way of understanding prime numbers.