Calling all maths detectives!

Can you solve the mysteries hidden in our carefully selected NRICH tasks?

Can you solve the mysteries hidden in our carefully selected NRICH tasks?

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### Codebreakers

This article for Primary and Secondary teachers is all about the mathematics behind solving puzzles, unravelling mysteries and breaking codes.

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### Count The Digits

In this investigation we are going to count the number of 1s, 2s, 3s etc in numbers. Can you predict what will happen?

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### I Like ...

Mr Gilderdale is playing a game with his class. What rule might he have chosen? How would you test your idea?

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### Secret Number

Annie and Ben are playing a game with a calculator. What was Annie's secret number?

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### What number?

I am less than 25. My ones digit is twice my tens digit. My digits add up to an even number.

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### Coded hundred square

This 100 square jigsaw is written in code. It starts with 1 and ends with 100. Can you build it up?

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### Mystery Matrix

Can you fill in this table square? The numbers 2 -12 were used to generate it with just one number used twice.

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### Curious number

Can you order the digits from 1-3 to make a number which is divisible by 3 so when the last digit is removed it becomes a 2-figure number divisible by 2, and so on?

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### Satisfying Four Statements

Can you find any two-digit numbers that satisfy all of these statements?