Watch our videos of multiplication methods that you may not have met before. Can you make sense of them?
Exploring the structure of a number square: how quickly can you put the number tiles in the right place on the grid?
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
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?
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. . . .
This article for the young and old talks about the origins of our number system and the important role zero has to play in it.
There are six numbers written in five different scripts. Can you sort out which is which?
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.
How many positive integers less than or equal to 4000 can be
written down without using the digits 7, 8 or 9?
The number 3723(in base 10) is written as 123 in another base. What
is that base?
four strategy dice games to consolidate pupils' understanding of rounding.
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!
Take any two digit number, for example 58. What do you have to do to reverse the order of the digits? Can you find a rule for reversing the order of digits for any two digit 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?
How many six digit numbers are there which DO NOT contain a 5?
Replace each letter with a digit to make this addition correct.
Which is quicker, counting up to 30 in ones or counting up to 300 in tens? Why?
What is the sum of all the digits in all the integers from one to
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 is a game in which your counters move in a spiral round the snail's shell. It is about understanding tens and units.
This activity involves rounding four-digit numbers to the nearest thousand.
Can you replace the letters with numbers? Is there only one
solution in each case?
Can you complete this calculation by filling in the missing numbers? In how many different ways can you do it?
Some Games That May Be Nice or Nasty for an adult and child. Use your knowledge of place value to beat your oponent.
Three people chose this as a favourite problem. It is the sort of
problem that needs thinking time - but once the connection is made
it gives access to many similar ideas.
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.
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
Can you work out some different ways to balance this equation?
The letters in the following addition sum represent the digits 1
... 9. If A=3 and D=2, what number is represented by "CAYLEY"?
Think of a two digit number, reverse the digits, and add the numbers together. Something special happens...
What happens when you round these numbers to the nearest whole number?
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?
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?
Use two dice to generate two numbers with one decimal place. 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...
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?
Have a go at balancing this equation. Can you find different ways of doing it?
What happens when you round these three-digit numbers to the nearest 100?
Amazing as it may seem the three fives remaining in the following
`skeleton' are sufficient to reconstruct the entire long division
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. . . .
How many solutions can you find to this sum? Each of the different letters stands for a different 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?
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
Can you substitute numbers for the letters in these sums?
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?
Find the values of the nine letters in the sum: FOOT + BALL = GAME
Follow the clues to find the mystery number.