Choose two digits and arrange them to make two double-digit
numbers. Now add your double-digit numbers. Now add your single
digit numbers. Divide your double-digit answer by your single-digit
answer. . . .
Replace each letter with a digit to make this addition correct.
Consider all of the five digit numbers which we can form using only
the digits 2, 4, 6 and 8. If these numbers are arranged in
ascending order, what is the 512th number?
Which is quicker, counting up to 30 in ones or counting up to 300 in tens? Why?
This is a game in which your counters move in a spiral round the snail's shell. It is about understanding tens and units.
How many positive integers less than or equal to 4000 can be
written down without using the digits 7, 8 or 9?
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?
How many six digit numbers are there which DO NOT contain a 5?
There are two forms of counting on Vuvv - Zios count in base 3 and
Zepts count in base 7. One day four of these creatures, two Zios
and two Zepts, sat on the summit of a hill to count the legs of. . . .
Who said that adding couldn't be fun?
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
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" .
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.
The number 3723(in base 10) is written as 123 in another base. What
is that base?
This activity involves rounding four-digit numbers to the nearest thousand.
There are six numbers written in five different scripts. Can you sort out which is which?
When asked how old she was, the teacher replied: My age in years is
not prime but odd and when reversed and added to my age you have a
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?
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?
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
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 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
There are nasty versions of this dice game but we'll start with the nice ones...
This 100 square jigsaw is written in code. It starts with 1 and ends with 100. Can you build it up?
Can you replace the letters with numbers? Is there only one solution in each case?
The letters in the following addition sum represent the digits 1
... 9. If A=3 and D=2, what number is represented by "CAYLEY"?
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?
Can you complete this calculation by filling in the missing numbers? In how many different ways can you do it?
Exploring the structure of a number square: how quickly can you put the number tiles in the right place on the grid?
Can you work out some different ways to balance this equation?
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?
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?
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 to work on with others.
Number problems at primary level that require careful consideration.
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?
Number problems for inquiring primary learners.
Number problems at primary level that may require determination.
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?
Nowadays the calculator is very familiar to many of us. What did
people do to save time working out more difficult problems before
the calculator existed?
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 three-digit numbers to the nearest 100?
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. . . .
Four strategy dice games to consolidate pupils' understanding of rounding.
Have a go at balancing this equation. Can you find different ways of doing it?
Find the sum of all three-digit numbers each of whose digits is
In the multiplication calculation, some of the digits have been replaced by letters and others by asterisks. Can you reconstruct the original multiplication?
Some Games That May Be Nice or Nasty for an adult and child. Use your knowledge of place value to beat your opponent.
Dicey Operations for an adult and child. Can you get close to 1000 than your partner?