problem

### Skeleton

Amazing as it may seem the three fives remaining in the following `skeleton' are sufficient to reconstruct the entire long division sum.

problem
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Skeleton

Amazing as it may seem the three fives remaining in the following `skeleton' are sufficient to reconstruct the entire long division sum.

problem
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What numbers can we make now?

Favourite

Imagine we have four bags containing numbers from a sequence. What numbers can we make now?

article
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Public Key Cryptography

An introduction to coding and decoding messages and the maths behind how to secretly share information.

problem
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Division Rules

Favourite

This challenge encourages you to explore dividing a three-digit number by a single-digit number.

problem
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What numbers can we make?

Favourite

Imagine we have four bags containing a large number of 1s, 4s, 7s and 10s. What numbers can we make?

problem
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Curious number

Favourite

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?

problem
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Newspaper Sheets

From only the page numbers on one sheet of newspaper, can you work out how many sheets there are altogether?

problem
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Indivisible

Each time a class lines up in different sized groups, a different number of people are left over. How large can the class be?

problem
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Gran, how old are you?

When Charlie asked his grandmother how old she is, he didn't get a
straightforward reply! Can you work out how old she is?