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?
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?
Each child in Class 3 took four numbers out of the bag. Who had made the highest even number?
Which is quicker, counting up to 30 in ones or counting up to 300 in tens? Why?
There are six numbers written in five different scripts. Can you sort out which is which?
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?
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?
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.
Number problems at primary level that may require determination.
Explore the relationship between simple linear functions and their graphs.
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?
This multiplication uses each of the digits 0 - 9 once and once only. Using the information given, can you replace the stars in the calculation with figures?
Number problems at primary level to work on with others.
Can you replace the letters with numbers? Is there only one solution in each case?
Number problems for inquiring primary learners.
In the multiplication calculation, some of the digits have been replaced by letters and others by asterisks. Can you reconstruct the original multiplication?
What do the digits in the number fifteen add up to? How many other numbers have digits with the same total but no zeros?
Follow the clues to find the mystery number.
What is the sum of all the digits in all the integers from one to one million?
Have a go at balancing this equation. Can you find different ways of doing it?
Choose any 3 digits and make a 6 digit number by repeating the 3 digits in the same order (e.g. 594594). Explain why whatever digits you choose the number will always be divisible by 7, 11 and 13.
This activity involves rounding four-digit numbers to the nearest thousand.
Exploring the structure of a number square: how quickly can you put the number tiles in the right place on the grid?
Find the sum of all three-digit numbers each of whose digits is odd.
Can you work out some different ways to balance this equation?
Can you complete this calculation by filling in the missing numbers? In how many different ways can you do it?
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?
Powers of numbers behave in surprising ways. Take a look at some of these and try to explain why they are true.
What happens when you round these three-digit numbers to the nearest 100?
Use two dice to generate two numbers with one decimal place. What happens when you round these numbers to the nearest whole number?
Some Games That May Be Nice or Nasty for an adult and child. Use your knowledge of place value to beat your opponent.
This is a game in which your counters move in a spiral round the snail's shell. It is about understanding tens and units.
Amazing as it may seem the three fives remaining in the following `skeleton' are sufficient to reconstruct the entire long division sum.
Who said that adding couldn't be fun?
Number problems at primary level that require careful consideration.
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?
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?
Can you substitute numbers for the letters in these sums?
Watch our videos of multiplication methods that you may not have met before. Can you make sense of them?
The number 3723(in base 10) is written as 123 in another base. What is that base?
A three digit number abc is always divisible by 7 when 2a+3b+c is divisible by 7. Why?
Can you show that 1^99 + 2^99 + 3^99 + 4^99 + 5^99 is divisible by 5?
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" .
A church hymn book contains 700 hymns. The numbers of the hymns are displayed by combining special small single-digit boards. What is the minimum number of small boards that is needed?
Take the numbers 1, 2, 3, 4 and 5 and imagine them written down in every possible order to give 5 digit numbers. Find the sum of the resulting numbers.
How many solutions can you find to this sum? Each of the different letters stands for a different number.
This 100 square jigsaw is written in code. It starts with 1 and ends with 100. Can you build it up?
What happens when you round these numbers to the nearest whole number?
There are nasty versions of this dice game but we'll start with the nice ones...
Take any four digit number. Move the first digit to the 'back of the queue' and move the rest along. Now add your two numbers. What properties do your answers always have?