A game that tests your understanding of remainders.
Gabriel multiplied together some numbers and then erased them. Can you figure out where each number was?
Do you know a quick way to check if a number is a multiple of two? How about three, four or six?
The clues for this Sudoku are the product of the numbers in adjacent squares.
What is the smallest number of answers you need to reveal in order to work out the missing headers?
Can you find a relationship between the number of dots on the circle and the number of steps that will ensure that all points are hit?
Is there an efficient way to work out how many factors a large number has?
Play the divisibility game to create numbers in which the first two digits make a number divisible by 2, the first three digits make a number divisible by 3...
Can you find any two-digit numbers that satisfy all of these statements?
A student in a maths class was trying to get some information from her teacher. She was given some clues and then the teacher ended by saying, "Well, how old are they?"
Can you find a way to identify times tables after they have been shifted up?
Given the products of adjacent cells, can you complete this Sudoku?
What is the remainder when 2^2002 is divided by 7? What happens with different powers of 2?
Find a cuboid (with edges of integer values) that has a surface area of exactly 100 square units. Is there more than one? Can you find them all?
Starting with the number 180, take away 9 again and again, joining up the dots as you go. Watch out - don't join all the dots!
The five digit number A679B, in base ten, is divisible by 72. What are the values of A and B?
The number 8888...88M9999...99 is divisible by 7 and it starts with the digit 8 repeated 50 times and ends with the digit 9 repeated 50 times. What is the value of the digit M?
A game for 2 people using a pack of cards Turn over 2 cards and try to make an odd number or a multiple of 3.
6! = 6 x 5 x 4 x 3 x 2 x 1. The highest power of 2 that divides exactly into 6! is 4 since (6!) / (2^4 ) = 45. What is the highest power of two that divides exactly into 100!?
A game for 2 or more people. Starting with 100, subratct a number from 1 to 9 from the total. You score for making an odd number, a number ending in 0 or a multiple of 6.
Ben passed a third of his counters to Jack, Jack passed a quarter of his counters to Emma and Emma passed a fifth of her counters to Ben. After this they all had the same number of counters.
How many numbers less than 1000 are NOT divisible by either: a) 2 or 5; or b) 2, 5 or 7?
I put eggs into a basket in groups of 7 and noticed that I could easily have divided them into piles of 2, 3, 4, 5 or 6 and always have one left over. How many eggs were in the basket?
A number N is divisible by 10, 90, 98 and 882 but it is NOT divisible by 50 or 270 or 686 or 1764. It is also known that N is a factor of 9261000. What is N?
Got It game for an adult and child. How can you play so that you know you will always win?
What is the value of the digit A in the sum below: [3(230 + A)]^2 = 49280A
Find the number which has 8 divisors, such that the product of the divisors is 331776.
Here is a machine with four coloured lights. Can you develop a strategy to work out the rules controlling each light?
Can you explain the strategy for winning this game with any target?
I'm thinking of a number. When my number is divided by 5 the remainder is 4. When my number is divided by 3 the remainder is 2. Can you find my number?
Using the digits 1 to 9, the number 4396 can be written as the product of two numbers. Can you find the factors?
Imagine a wheel with different markings painted on it at regular intervals. Can you predict the colour of the 18th mark? The 100th mark?
Find the frequency distribution for ordinary English, and use it to help you crack the code.
The number 12 = 2^2 × 3 has 6 factors. What is the smallest natural number with exactly 36 factors?
How many integers between 1 and 1200 are NOT multiples of any of the numbers 2, 3 or 5?
Which is quicker, counting up to 30 in ones or counting up to 300 in tens? Why?
The sum of the first 'n' natural numbers is a 3 digit number in which all the digits are the same. How many numbers have been summed?
What is the lowest number which always leaves a remainder of 1 when divided by each of the numbers from 2 to 10?
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 mathematician goes into a supermarket and buys four items. Using a calculator she multiplies the cost instead of adding them. How can her answer be the same as the total at the till?
A three digit number abc is always divisible by 7 when 2a+3b+c is divisible by 7. Why?
Follow this recipe for sieving numbers and see what interesting patterns emerge.
Imagine we have four bags containing numbers from a sequence. What numbers can we make now?
This article for teachers describes how number arrays can be a useful reprentation for many number concepts.
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?
These red, yellow and blue spinners were each spun 45 times in total. Can you work out which numbers are on each spinner?
Which pairs of cogs let the coloured tooth touch every tooth on the other cog? Which pairs do not let this happen? Why?
In a square in which the houses are evenly spaced, numbers 3 and 10 are opposite each other. What is the smallest and what is the largest possible number of houses in the square?
I am thinking of three sets of numbers less than 101. They are the red set, the green set and the blue set. Can you find all the numbers in the sets from these clues?
Twice a week I go swimming and swim the same number of lengths of the pool each time. As I swim, I count the lengths I've done so far, and make it into a fraction of the whole number of lengths I. . . .