This addition sum uses all ten digits 0, 1, 2...9 exactly once. Find the sum and show that the one you give is the only possibility.

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?

This activity involves rounding four-digit numbers to the nearest thousand.

Can you arrange the digits 1,2,3,4,5,6,7,8,9 into three 3-digit numbers such that their total is close to 1500?

Number problems at primary level that may require determination.

The Scot, John Napier, invented these strips about 400 years ago to help calculate multiplication and division. Can you work out how to use Napier's bones to find the answer to these multiplications?

Choose four different digits from 1-9 and put one in each box so that the resulting four two-digit numbers add to a total of 100.

Use two dice to generate two numbers with one decimal place. What happens when you round these numbers to the nearest whole number?

Number problems at primary level to work on with others.

What happens when you round these three-digit numbers to the nearest 100?

What is the sum of all the digits in all the integers from one to one million?

Find out what a Deca Tree is and then work out how many leaves there will be after the woodcutter has cut off a trunk, a branch, a twig and a leaf.

A car's milometer reads 4631 miles and the trip meter has 173.3 on it. How many more miles must the car travel before the two numbers contain the same digits in the same order?

The letters in the following addition sum represent the digits 1 ... 9. If A=3 and D=2, what number is represented by "CAYLEY"?

Each child in Class 3 took four numbers out of the bag. Who had made the highest even number?

What happens when you round these numbers to the nearest whole number?

Find the values of the nine letters in the sum: FOOT + BALL = GAME

The number 3723(in base 10) is written as 123 in another base. What is that base?

Carry out cyclic permutations of nine digit numbers containing the digits from 1 to 9 (until you get back to the first number). Prove that whatever number you choose, they will add to the same total.

In the multiplication calculation, some of the digits have been replaced by letters and others by asterisks. Can you reconstruct the original multiplication?

How many solutions can you find to this sum? Each of the different letters stands for a different number.

Pick the number of times a week that you eat chocolate. This number must be more than one but less than ten. Multiply this number by 2. Add 5 (for Sunday). Multiply by 50... Can you explain why it. . . .

Think of a two digit number, reverse the digits, and add the numbers together. Something special happens...

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

Exploring the structure of a number square: how quickly can you put the number tiles in the right place on the grid?

Can you replace the letters with numbers? Is there only one solution in each case?

This is a game in which your counters move in a spiral round the snail's shell. It is about understanding tens and units.

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?

There are six numbers written in five different scripts. Can you sort out which is which?

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

Using balancing scales what is the least number of weights needed to weigh all integer masses from 1 to 1000? Placing some of the weights in the same pan as the object how many are needed?

This 100 square jigsaw is written in code. It starts with 1 and ends with 100. Can you build it up?

Number problems for inquiring primary learners.

You have two sets of the digits 0 – 9. Can you arrange these in the five boxes to make four-digit numbers as close to the target numbers as possible?

Number problems at primary level that require careful consideration.

There are nasty versions of this dice game but we'll start with the nice ones...

In this 100 square, look at the green square which contains the numbers 2, 3, 12 and 13. What is the sum of the numbers that are diagonally opposite each other? What do you notice?

A school song book contains 700 songs. The numbers of the songs are displayed by combining special small single-digit boards. What is the minimum number of small boards that is needed?

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?

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

Watch our videos of multiplication methods that you may not have met before. Can you make sense of them?

When the number x 1 x x x is multiplied by 417 this gives the answer 9 x x x 0 5 7. Find the missing digits, each of which is represented by an "x" .

32 x 38 = 30 x 40 + 2 x 8; 34 x 36 = 30 x 40 + 4 x 6; 56 x 54 = 50 x 60 + 6 x 4; 73 x 77 = 70 x 80 + 3 x 7 Verify and generalise if possible.

This article, written for teachers, looks at the different kinds of recordings encountered in Primary Mathematics lessons and the importance of not jumping to conclusions!

What do the digits in the number fifteen add up to? How many other numbers have digits with the same total but no zeros?