Reasoning, convincing and proving

problem
Digit discovery

Age

7 to 11

Challenge level

Here is an interesting property about two sets of digits. Can you work out what the digits might be?
problem
Xavi's T-shirt

Age

7 to 16

Challenge level

How much can you read into a t-shirt?
problem
What numbers can we make now?

Age

11 to 14

Challenge level

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

Age

16 to 18

Challenge level

Three of Santa's elves and their best friends are sitting down to a festive feast. Can you find the probability that each elf sits next to their bestie?
problem
More less is more

Age

7 to 14

Challenge level

In each of these games, you will need a little bit of luck, and your knowledge of place value to develop a winning strategy.
page
Mathdoku demonstration

This video of Charlie and Liz solving a 6 by 6 Mathdoku may give you ideas for strategies to try.
problem
6 by 6 Mathdokus

Age

7 to 16

Challenge level

Can you use the clues to complete these 6 by 6 Mathematical Sudokus?
problem
5 by 5 Mathdokus

Age

7 to 16

Challenge level

Can you use the clues to complete these 5 by 5 Mathematical Sudokus?
problem
4 by 4 Mathdokus

Age

7 to 14

Challenge level

Can you use the clues to complete these 4 by 4 Mathematical Sudokus?
problem
3 by 3 Mathdokus

Age

7 to 14

Challenge level

Can you use the clues to complete these 3 by 3 Mathematical Sudokus?