Addition and subtraction

problem
Eight dominoes

Age

7 to 16

Challenge level

Using the 8 dominoes make a square where each of the columns and rows adds up to 8
problem
Sheep talk

Age

7 to 11

Challenge level

In sheep talk the only letters used are B and A. A sequence of words is formed by following certain rules. What do you notice when you count the letters in each word?
problem
Cunning card trick

Age

11 to 14

Challenge level

Delight your friends with this cunning trick! Can you explain how it works?
problem
Three primes

Age

14 to 16

Challenge level

Weekly Problem 6 - 2010
Can you find three primes such that their product is exactly five times their sum? Do you think you have found all possibilities?
problem
Always, sometimes or never? KS1

Age

5 to 7

Challenge level

Are these statements relating to calculation and properties of shapes always true, sometimes true or never true?
problem
Homes

Age

5 to 7

Challenge level

Six new homes are being built! They can be detached, semi-detached or terraced houses. How many different combinations of these can you find?
problem
Two dice

Age

5 to 7

Challenge level

Find all the numbers that can be made by adding the dots on two dice.
problem
One big triangle

Age

5 to 7

Challenge level

Make one big triangle so the numbers that touch on the small triangles add to 10.
problem
Fair exchange

Age

5 to 7

Challenge level

In your bank, you have three types of coins. The number of spots shows how much they are worth. Can you choose coins to exchange with the groups given to make the same total?
problem
Butterfly flowers

Age

5 to 7

Challenge level

Can you find two butterflies to go on each flower so that the numbers on each pair of butterflies adds to the number on their flower?