Addition and subtraction

problem
Seven square numbers

Age

7 to 11

Challenge level

Add the sum of the squares of four numbers between 10 and 20 to the sum of the squares of three numbers less than 6 to make the square of another, larger, number.
problem
Marvellous matrix

Age

7 to 11

Challenge level

Follow the directions for circling numbers in the matrix. Add all the circled numbers together. Note your answer. Try again with a different starting number. What do you notice?
problem
Rod measures

Age

7 to 11

Challenge level

Using 3 rods of integer lengths, none longer than 10 units and not using any rod more than once, you can measure all the lengths in whole units from 1 to 10 units. How many ways can you do this?
problem
One million to seven

Age

7 to 11

Challenge level

Start by putting one million (1 000 000) into the display of your calculator. Can you reduce this to 7 using just the 7 key and add, subtract, multiply, divide and equals as many times as you like?
problem
Some secret codes

Age

7 to 11

Challenge level

Can you follow the rule to decode the messages?
problem
Dice in a corner

Age

7 to 11

Challenge level

How could you arrange at least two dice in a stack so that the total of the visible spots is 18?
problem
The dice train

Age

7 to 11

Challenge level

This dice train has been made using specific rules. How many different trains can you make?
problem
Subtraction surprise

Age

7 to 14

Challenge level

Try out these calculations. Are you surprised by the results?
game
Favourite

Countdown

Age

7 to 14

Challenge level

Here is a chance to play a version of the classic Countdown Game.
game
Favourite

Dicey operations

Age

7 to 14

Challenge level

In these addition and subtraction games, you'll need to think strategically to get closest to the target.