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.
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?
Number problems at primary level to work on with others.
Can you work out some different ways to balance this equation?
Number problems at primary level that require careful consideration.
Can you complete this calculation by filling in the missing numbers? In how many different ways can you do it?
Find the sum of all three-digit numbers each of whose digits is
What do the digits in the number fifteen add up to? How many other
numbers have digits with the same total but no zeros?
Have a go at balancing this equation. Can you find different ways of doing it?
Which is quicker, counting up to 30 in ones or counting up to 300 in tens? Why?
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?
Can you substitute numbers for the letters in these sums?
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?
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?
Can you replace the letters with numbers? Is there only one solution in each case?
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?
Who said that adding couldn't be fun?
What happens when you round these three-digit numbers to the nearest 100?
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?
In the multiplication calculation, some of the digits have been replaced by letters and others by asterisks. Can you reconstruct the original multiplication?
Follow the clues to find the mystery number.
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.
What is the sum of all the digits in all the integers from one to
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?
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?
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?
Each child in Class 3 took four numbers out of the bag. Who had
made the highest even number?
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?
Investigate the different ways these aliens count in this
challenge. You could start by thinking about how each of them would
write our number 7.
Explore the relationship between simple linear functions and their
This is a game in which your counters move in a spiral round the snail's shell. It is about understanding tens and units.
There are six numbers written in five different scripts. Can you sort out which is which?
Powers of numbers behave in surprising ways. Take a look at some of these and try to explain why they are true.
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?
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" .
Number problems for inquiring primary learners.
Exploring the structure of a number square: how quickly can you put the number tiles in the right place on the grid?
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
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.
Amazing as it may seem the three fives remaining in the following
`skeleton' are sufficient to reconstruct the entire long division
How many six digit numbers are there which DO NOT contain a 5?
This activity involves rounding four-digit numbers to the nearest thousand.
Can you show that 1^99 + 2^99 + 3^99 + 4^99 + 5^99 is divisible by
Four strategy dice games to consolidate pupils' understanding of rounding.
How many solutions can you find to this sum? Each of the different letters stands for a different number.
Find the values of the nine letters in the sum: FOOT + BALL = GAME