Each light in this interactivity turns on according to a rule. What happens when you enter different numbers? Can you find the smallest number that lights up all four lights?

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

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?

Nearly all of us have made table patterns on hundred squares, that is 10 by 10 grids. This problem looks at the patterns on differently sized square grids.

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

Place four pebbles on the sand in the form of a square. Keep adding as few pebbles as necessary to double the area. How many extra pebbles are added each time?

What do the numbers shaded in blue on this hundred square have in common? What do you notice about the pink numbers? How about the shaded numbers in the other squares?

This package will help introduce children to, and encourage a deep exploration of, multiples.

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

Arrange the four number cards on the grid, according to the rules, to make a diagonal, vertical or horizontal line.

Nine squares with side lengths 1, 4, 7, 8, 9, 10, 14, 15, and 18 cm can be fitted together to form a rectangle. What are the dimensions of the rectangle?

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

Kimie and Sebastian were making sticks from interlocking cubes and lining them up. Can they make their lines the same length? Can they make any other lines?

Can you fill in this table square? The numbers 2 -12 were used to generate it with just one number used twice.

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?

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

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

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?

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

Look at three 'next door neighbours' amongst the counting numbers. Add them together. What do you notice?

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

Use cubes to continue making the numbers from 7 to 20. Are they sticks, rectangles or squares?

Got It game for an adult and child. How can you play so that you know you will always win?

Use the interactivity to sort these numbers into sets. Can you give each set a name?

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?

The planet of Vuvv has seven moons. Can you work out how long it is between each super-eclipse?

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

Can you order the digits from 1-3 to make a number which is divisible by 3 so when the last digit is removed it becomes a 2-figure number divisible by 2, and so on?

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?

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

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

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

If you count from 1 to 20 and clap more loudly on the numbers in the two times table, as well as saying those numbers loudly, which numbers will be loud?

Suppose we allow ourselves to use three numbers less than 10 and multiply them together. How many different products can you find? How do you know you've got them all?

Can you work out the arrangement of the digits in the square so that the given products are correct? The numbers 1 - 9 may be used once and once only.

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

How many different shaped boxes can you design for 36 sweets in one layer? Can you arrange the sweets so that no sweets of the same colour are next to each other in any direction?

In this activity, the computer chooses a times table and shifts it. Can you work out the table and the shift each time?

In a square in which the houses are evenly spaced, numbers 3 and 10 are opposite each other. What is the smallest and what is the largest possible number of houses in the square?

Does a graph of the triangular numbers cross a graph of the six times table? If so, where? Will a graph of the square numbers cross the times table too?

A game in which players take it in turns to choose a number. Can you block your opponent?

A game that tests your understanding of remainders.

Complete the magic square using the numbers 1 to 25 once each. Each row, column and diagonal adds up to 65.

Use the interactivities to complete these Venn diagrams.

Number problems at primary level to work on with others.

Number problems at primary level that may require determination.

An environment which simulates working with Cuisenaire rods.