Take any pair of numbers, say 9 and 14. Take the larger number, fourteen, and count up in 14s. Then divide each of those values by the 9, and look at the remainders.
What is the smallest number of answers you need to reveal in order to work out the missing headers?
Given the products of adjacent cells, can you complete this Sudoku?
How many integers between 1 and 1200 are NOT multiples of any of the numbers 2, 3 or 5?
In how many ways can the number 1 000 000 be expressed as the product of three positive integers?
Data is sent in chunks of two different sizes - a yellow chunk has 5 characters and a blue chunk has 9 characters. A data slot of size 31 cannot be exactly filled with a combination of yellow and. . . .
Can you make lines of Cuisenaire rods that differ by 1?
Given the products of diagonally opposite cells - can you complete this Sudoku?
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?"
Which pairs of cogs let the coloured tooth touch every tooth on the other cog? Which pairs do not let this happen? Why?
The clues for this Sudoku are the product of the numbers in adjacent squares.
Caroline and James pick sets of five numbers. Charlie chooses three of them that add together to make a multiple of three. Can they stop him?
An environment which simulates working with Cuisenaire rods.
How many zeros are there at the end of the number which is the product of first hundred positive integers?
The puzzle can be solved by finding the values of the unknown digits (all indicated by asterisks) in the squares of the $9\times9$ grid.
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?
Substitution and Transposition all in one! How fiendish can these codes get?
Using the digits 1, 2, 3, 4, 5, 6, 7 and 8, mulitply a two two digit numbers are multiplied to give a four digit number, so that the expression is correct. How many different solutions can you find?
The items in the shopping basket add and multiply to give the same amount. What could their prices be?
Got It game for an adult and child. How can you play so that you know you will always win?
Arrange the four number cards on the grid, according to the rules, to make a diagonal, vertical or horizontal line.
Can you explain the strategy for winning this game with any target?
Gabriel multiplied together some numbers and then erased them. Can you figure out where each number was?
Find the largest integer which divides every member of the following sequence: 1^5-1, 2^5-2, 3^5-3, ... n^5-n.
Follow this recipe for sieving numbers and see what interesting patterns emerge.
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 two people, or play online. Given a target number, say 23, and a range of numbers to choose from, say 1-4, players take it in turns to add to the running total to hit their target.
Can you find any perfect numbers? Read this article to find out more...
The number 12 = 2^2 × 3 has 6 factors. What is the smallest natural number with exactly 36 factors?
Find some triples of whole numbers a, b and c such that a^2 + b^2 + c^2 is a multiple of 4. Is it necessarily the case that a, b and c must all be even? If so, can you explain why?
Each letter represents a different positive digit AHHAAH / JOKE = HA What are the values of each of the letters?
I'm thinking of a number. My number is both a multiple of 5 and a multiple of 6. What could my number be?
Find the highest power of 11 that will divide into 1000! exactly.
Imagine we have four bags containing a large number of 1s, 4s, 7s and 10s. What numbers can we make?
Can you find any two-digit numbers that satisfy all of these statements?
Factors and Multiples game for an adult and child. How can you make sure you win this game?
How did the the rotation robot make these patterns?
Imagine we have four bags containing numbers from a sequence. What numbers can we make now?
Can you work out what size grid you need to read our secret message?
Factor track is not a race but a game of skill. The idea is to go round the track in as few moves as possible, keeping to the rules.
Here is a machine with four coloured lights. Can you develop a strategy to work out the rules controlling each light?
Can you find a cuboid that has a surface area of exactly 100 square units. Is there more than one? Can you find them all?
Can you work out how many lengths I swim each day?
Can you find a way to identify times tables after they have been shifted up or down?
Play this game and see if you can figure out the computer's chosen number.
You are given the Lowest Common Multiples of sets of digits. Find the digits and then solve the Sudoku.
I added together the first 'n' positive integers and found that my answer was a 3 digit number in which all the digits were the same...
Ben, Jack and Emma passed counters to each other and ended with the same number of counters. How many did they start with?
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...
I added together some of my neighbours' house numbers. Can you explain the patterns I noticed?