Investigate which numbers make these lights come on. What is the smallest number you can find that lights up all the lights?

Pat counts her sweets in different groups and both times she has some left over. How many sweets could she have had?

Can you see how these factor-multiple chains work? Find the chain which contains the smallest possible numbers. How about the largest possible numbers?

If there is a ring of six chairs and thirty children must either sit on a chair or stand behind one, how many children will be behind each chair?

Ben and his mum are planting garlic. Use the interactivity to help you find out how many cloves of garlic they might have had.

Can you find the chosen number from the grid using the clues?

This big box multiplies anything that goes inside it by the same number. If you know the numbers that come out, what multiplication might be going on in the box?

You can make a calculator count for you by any number you choose. You can count by ones to reach 24. You can count by twos to reach 24. What else can you count by to reach 24?

Four of these clues are needed to find the chosen number on this grid and four are true but do nothing to help in finding the number. Can you sort out the clues and find the number?

"Ip dip sky blue! Who's 'it'? It's you!" Where would you position yourself so that you are 'it' if there are two players? Three players ...?

Four of these clues are needed to find the chosen number on this grid and four are true but do nothing to help in finding the number. Can you sort out the clues and find the number?

Mr Gilderdale is playing a game with his class. What rule might he have chosen? How would you test your idea?

Becky created a number plumber which multiplies by 5 and subtracts 4. What do you notice about the numbers that it produces? Can you explain your findings?

Frances and Rishi were given a bag of lollies. They shared them out evenly and had one left over. How many lollies could there have been in the bag?

Which is quicker, counting up to 30 in ones or counting up to 300 in tens? Why?

Can you work out how to balance this equaliser? You can put more than one weight on a hook.

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

Use this grid to shade the numbers in the way described. Which numbers do you have left? Do you know what they are called?

Look at the squares in this problem. What does the next square look like? I draw a square with 81 little squares inside it. How long and how wide is my square?

There are ten children in Becky's group. Can you find a set of numbers for each of them? Are there any other sets?

In this maze of hexagons, you start in the centre at 0. The next hexagon must be a multiple of 2 and the next a multiple of 5. What are the possible paths you could take?

An environment which simulates working with Cuisenaire rods.

Find the squares that Froggie skips onto to get to the pumpkin patch. She starts on 3 and finishes on 30, but she lands only on a square that has a number 3 more than the square she skips from.

How many trains can you make which are the same length as Matt's, using rods that are identical?

Can you complete this jigsaw of the multiplication square?

I am thinking of three sets of numbers less than 101. Can you find all the numbers in each set from these clues?

A game for 2 or more people. Starting with 100, subratct a number from 1 to 9 from the total. You score for making an odd number, a number ending in 0 or a multiple of 6.

On the planet Vuv there are two sorts of creatures. The Zios have 3 legs and the Zepts have 7 legs. The great planetary explorer Nico counted 52 legs. How many Zios and how many Zepts were there?

These red, yellow and blue spinners were each spun 45 times in total. Can you work out which numbers are on each spinner?

A game for 2 people using a pack of cards Turn over 2 cards and try to make an odd number or a multiple of 3.

Benâ€™s class were cutting up number tracks. First they cut them into twos and added up the numbers on each piece. What patterns could they see?

I am thinking of three sets of numbers less than 101. They are the red set, the green set and the blue set. Can you find all the numbers in the sets from these clues?

This article for teachers describes how number arrays can be a useful reprentation for many number concepts.

What is the lowest number which always leaves a remainder of 1 when divided by each of the numbers from 2 to 10?

Investigate the smallest number of moves it takes to turn these mats upside-down if you can only turn exactly three at a time.

Is it possible to draw a 5-pointed star without taking your pencil off the paper? Is it possible to draw a 6-pointed star in the same way without taking your pen off?

Can you work out some different ways to balance this equation?

Norrie sees two lights flash at the same time, then one of them flashes every 4th second, and the other flashes every 5th second. How many times do they flash together during a whole minute?

Have a go at balancing this equation. Can you find different ways of doing it?

56 406 is the product of two consecutive numbers. What are these two numbers?

Number problems at primary level that may require resilience.

How many different sets of numbers with at least four members can you find in the numbers in this box?

How can you use just one weighing to find out which box contains the lighter ten coins out of the ten boxes?

Can you complete this calculation by filling in the missing numbers? In how many different ways can you do it?