Addition and Subtraction

problem

Poly plug rectangles

Age

5 to 11

Challenge level

The computer has made a rectangle and will tell you the number of spots it uses in total. Can you find out where the rectangle is?

problem

What was in the box?

Age

5 to 7

Challenge level

This box does something to the numbers that go into it. If you know the numbers that come out, what might be going on inside the box?

problem

Doing and undoing

Age

5 to 11

Challenge level

An investigation looking at doing and undoing mathematical operations focusing on doubling, halving, adding and subtracting.

problem

How do you see it?

Age

5 to 11

Challenge level

Here are some short problems for you to try. Talk to your friends about how you work them out.

interactivity

Cuisenaire environment

Age

5 to 16

Challenge level

An environment which simulates working with Cuisenaire rods.

problem

Two spinners

Age

5 to 7

Challenge level

What two-digit numbers can you make with these two dice? What can't you make?

project

How many?

This project challenges you to work out the number of cubes hidden under a cloth. What questions would you like to ask?

$What Could \It Be?$

problem

What could it be?

Age

5 to 7

Challenge level

In this calculation, the box represents a missing digit. What could the digit be? What would the solution be in each case?

problem

Unit differences

Age

5 to 7

Challenge level

This challenge is about finding the difference between numbers which have the same tens digit.

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

Dicey addition

Age

5 to 11

Challenge level

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

problem

Arranging additions and sorting subtractions

Age

5 to 7

Challenge level

Order these four calculations from easiest to hardest. How did you decide?

problem

Subtraction slip

Age

5 to 7

Challenge level

Can you spot the mistake in this video? How would you work out the answer to this calculation?

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

Equivalent pairs

Age

5 to 7

Challenge level

Can you match pairs of cards which show the same amount?

Two flowers with the numbers 15 and 16 on them

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?

problem

What's in a name?

Age

5 to 7

Challenge level

What do you notice about these squares of numbers? What is the same? What is different?

problem

Cuisenaire counting

Age

5 to 7

Challenge level

Here are some rods that are different colours. How could I make a yellow rod using white and red rods?

problem

Number balance

Age

5 to 7

Challenge level

Can you hang weights in the right place to make the the number balance balanced?

problem

Domino sorting

Age

5 to 7

Challenge level

Try grouping the dominoes in the ways described. Are there any left over each time? Can you explain why?

problem

Number lines

Age

5 to 7

Challenge level

Leah and Tom each have a number line. Can you work out where their counters will land?

problem

Strike it out

Age

5 to 11

Challenge level

Use your addition and subtraction skills, combined with some strategic thinking, to beat your partner at this game.

problem

Sort them out (1)

Age

5 to 7

Challenge level

Can you each work out the number on your card? What do you notice? How could you sort the cards?

problem

Sitting round the party tables

Age

5 to 11

Challenge level

Sweets are given out to party-goers in a particular way. Investigate the total number of sweets received by people sitting in different positions.

problem

Pairs of numbers

Age

5 to 7

Challenge level

If you have ten counters numbered 1 to 10, how many can you put into pairs that add to 10? Which ones do you have to leave out? Why?

problem

The add and take-away path

Age

5 to 7

Challenge level

Two children made up a game as they walked along the garden paths. Can you find out their scores? Can you find some paths of your own?

problem

Half time

Age

5 to 11

Challenge level

What could the half time scores have been in these Olympic hockey matches?

problem

Jumping squares

Age

5 to 7

Challenge level

In this problem it is not the squares that jump, you do the jumping! The idea is to go round the track in as few jumps as possible.

problem

Noah

Age

5 to 7

Challenge level

Noah saw 12 legs walk by into the Ark. How many creatures did he see?

problem

Birthday cakes

Age

5 to 7

Challenge level

Jack's mum bought some candles to use on his birthday cakes and when his sister was born, she used them on her cakes too. Can you use the information to find out when Kate was born?

problem

Heads and feet

Age

5 to 7

Challenge level

On a farm there were some hens and sheep. Altogether there were 8 heads and 22 feet. How many hens were there?

problem

Ladybirds in the garden

Age

5 to 7

Challenge level

In Sam and Jill's garden there are two sorts of ladybirds with 7 spots or 4 spots. What numbers of total spots can you make?

problem

Eggs in baskets

Age

5 to 7

Challenge level

There are three baskets, a brown one, a red one and a pink one, holding a total of 10 eggs. How many eggs are in each basket?

problem

Secret number

Age

5 to 7

Challenge level

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

problem

Find the difference

Age

5 to 7

Challenge level

Place the numbers 1 to 6 in the circles so that each number is the difference between the two numbers just below it.

problem

2, 4, 6, 8

Age

5 to 7

Challenge level

Using the cards 2, 4, 6, 8, +, - and =, what number statements can you make?

problem

Number round up

Age

5 to 7

Challenge level

Arrange the numbers 1 to 6 in each set of circles below. The sum of each side of the triangle should equal the number in its centre.

problem

The Brown family

Age

5 to 7

Challenge level

Use the information about Sally and her brother to find out how many children there are in the Brown family.

problem

The tall tower

Age

5 to 7

Challenge level

As you come down the ladders of the Tall Tower you collect useful spells. Which way should you go to collect the most spells?

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Addition and subtraction