Find the values of the nine letters in the sum: FOOT + BALL = GAME
The letters in the following addition sum represent the digits 1
... 9. If A=3 and D=2, what number is represented by "CAYLEY"?
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 oponent.
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?
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?
A game to be played against the computer, or in groups. Pick a 7-digit number. A random digit is generated. What must you subract to remove the digit from your number? the first to zero wins.
Can you replace the letters with numbers? Is there only one
solution in each case?
In the multiplication calculation, some of the digits have been replaced by letters and others by asterisks.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?
This is a game in which your counters move in a spiral round the snail's shell. It is about understanding tens and units.
Dicey Operations for an adult and child. Can you get close to 1000 than your partner?
Follow the clues to find the mystery number.
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.
There are six numbers written in five different scripts. Can you sort out which is which?
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 show that 1^99 + 2^99 + 3^99 + 4^99 + 5^99 is divisible by
Have a go at balancing this equation. Can you find different ways of doing it?
What is the sum of all the digits in all the integers from one to
Which is quicker, counting up to 30 in ones or counting up to 300 in tens? Why?
Can you work out some different ways to balance this equation?
Who said that adding, subtracting, multiplying and dividing
couldn't be fun?
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?
Can you complete this calculation by filling in the missing numbers? In how many different ways can you do it?
This 100 square jigsaw is written in code. It starts with 1 and ends with 100. Can you build it up?
This activity involves rounding four-digit numbers to the nearest thousand.
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?
Investigate which numbers make these lights come on. What is the smallest number you can find that lights up all the lights?
Amazing as it may seem the three fives remaining in the following
`skeleton' are sufficient to reconstruct the entire long division
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.
Can you substitute numbers for the letters in these sums?
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
Find the sum of all three-digit numbers each of whose digits is
Consider all two digit numbers (10, 11, . . . ,99). In writing down
all these numbers, which digits occur least often, and which occur
most often ? What about three digit numbers, four digit numbers. . . .
The number 27 is special because it is three times the sum of its digits 27 = 3 (2 + 7). Find some two digit numbers that are SEVEN times the sum of their digits (seven-up numbers)?
Choose four different digits from 1-9 and put one in each box so that the resulting four two-digit numbers add to a total of 100.
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!
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?
A three digit number abc is always divisible by 7 when 2a+3b+c is divisible by 7. Why?
Exploring the structure of a number square: how quickly can you put the number tiles in the right place on the grid?
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?
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?
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. . . .
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
Think of a two digit number, reverse the digits, and add the numbers together. Something special happens...
Replace each letter with a digit to make this addition correct.
How many six digit numbers are there which DO NOT contain a 5?
The number 3723(in base 10) is written as 123 in another base. What
is that base?