Challenge Level

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

Challenge Level

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

Challenge Level

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

Challenge Level

There is a clock-face where the numbers have become all mixed up. Can you find out where all the numbers have got to from these ten statements?

Challenge Level

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.

Challenge Level

48 is called an abundant number because it is less than the sum of its factors (without itself). Can you find some more abundant numbers?

Challenge Level

Number problems at primary level that may require resilience.

Challenge Level

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?

Challenge Level

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

Challenge Level

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

Challenge Level

Given the products of adjacent cells, can you complete this Sudoku?

Challenge Level

I throw three dice and get 5, 3 and 2. Add the scores on the three dice. What do you get? Now multiply the scores. What do you notice?

Challenge Level

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

Challenge Level

Can you make square numbers by adding two prime numbers together?

Challenge Level

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?

Challenge Level

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

Challenge Level

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

Challenge Level

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?

Challenge Level

When Charlie asked his grandmother how old she is, he didn't get a straightforward reply! Can you work out how old she is?

Challenge Level

Your vessel, the Starship Diophantus, has become damaged in deep space. Can you use your knowledge of times tables and some lightning reflexes to survive?

Challenge Level

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?

Challenge Level

Number problems at primary level to work on with others.

Challenge Level

Find the words hidden inside each of the circles by counting around a certain number of spaces to find each letter in turn.

Challenge Level

The discs for this game are kept in a flat square box with a square hole for each. Use the information to find out how many discs of each colour there are in the box.

Challenge Level

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?

Challenge Level

Play the divisibility game to create numbers in which the first two digits make a number divisible by 2, the first three digits make a number divisible by 3...

Challenge Level

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?

Challenge Level

Each clue in this Sudoku is the product of the two numbers in adjacent cells.

Challenge Level

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

Challenge Level

Play this game and see if you can figure out the computer's chosen number.

Challenge Level

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.

Challenge Level

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?

Challenge Level

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

Challenge Level

An investigation that gives you the opportunity to make and justify predictions.

Challenge Level

The clues for this Sudoku are the product of the numbers in adjacent squares.

Challenge Level

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?

Challenge Level

How many different rectangles can you make using this set of rods?

Challenge Level

Can you find different ways of creating paths using these paving slabs?

Challenge Level

Ben, Jack and Emma passed counters to each other and ended with the same number of counters. How many did they start with?

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

Challenge Level

Using the digits 1, 2, 3, 4, 5, 6, 7 and 8, mulitply a two two digit numbers are multiplied to give a four digit number, so that the expression is correct. How many different solutions can you find?

Challenge Level

Think of any three-digit number. Repeat the digits. The 6-digit number that you end up with is divisible by 91. Is this a coincidence?

Challenge Level

The puzzle can be solved by finding the values of the unknown digits (all indicated by asterisks) in the squares of the $9\times9$ grid.

Challenge Level

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

Challenge Level

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

Challenge Level

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

Challenge Level

The number 8888...88M9999...99 is divisible by 7 and it starts with the digit 8 repeated 50 times and ends with the digit 9 repeated 50 times. What is the value of the digit M?