Can you substitute numbers for the letters in these sums?
Number problems at primary level that require careful consideration.
Can you replace the letters with numbers? Is there only one solution in each case?
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?
What do the digits in the number fifteen add up to? How many other numbers have digits with the same total but no zeros?
Number problems at primary level that may require resilience.
This article for primary teachers encourages exploration of two fundamental ideas, exchange and 'unitising', which will help children become more fluent when calculating.
In the multiplication calculation, some of the digits have been replaced by letters and others by asterisks. Can you reconstruct the original multiplication?
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?
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.
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 odd.
Number problems at primary level to work on with others.
Have a go at balancing this equation. Can you find different ways of doing it?
Can you work out some different ways to balance this equation?
Follow the clues to find the mystery number.
Try out this number trick. What happens with different starting numbers? What do you notice?
In this article, Alf outlines six activities using the Gattegno chart, which help to develop understanding of place value, multiplication and division.
Alf describes how the Gattegno chart helped a class of 7-9 year olds gain an awareness of place value and of the inverse relationship between multiplication and division.
A school song book contains 700 songs. The numbers of the songs are displayed by combining special small single-digit cards. What is the minimum number of small cards that is needed?
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?
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?
What happens when you round these three-digit numbers to the nearest 100?
How many more miles must the car travel before the numbers on the milometer and the trip meter 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"?
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?
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?
Find the values of the nine letters in the sum: FOOT + BALL = GAME
Which is quicker, counting up to 30 in ones or counting up to 300 in tens? Why?
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?
Who said that adding couldn't be fun?
Number problems for inquiring primary learners.
Powers of numbers behave in surprising ways. Take a look at some of these and try to explain why they are true.
This 100 square jigsaw is written in code. It starts with 1 and ends with 100. Can you build it up?
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?
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?
Replace each letter with a digit to make this addition correct.
Use two dice to generate two numbers with one decimal place. What happens when you round these numbers to the nearest whole number?
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.
How many six digit numbers are there which DO NOT contain a 5?
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.
Take any four digit number. Move the first digit to the end and move the rest along. Now add your two numbers. Did you get a multiple of 11?
How many positive integers less than or equal to 4000 can be written down without using the digits 7, 8 or 9?
This challenge is to make up YOUR OWN alphanumeric. Each letter represents a digit and where the same letter appears more than once it must represent the same digit each time.
Use your knowledge of place value to try to win this game. How will you maximise your score?
Try out some calculations. Are you surprised by the results?
How many solutions can you find to this sum? Each of the different letters stands for a different number.
Some Games That May Be Nice or Nasty for an adult and child. Use your knowledge of place value to beat your opponent.
More upper primary number sense and place value tasks.