How many integers between 1 and 1200 are NOT multiples of any of the numbers 2, 3 or 5?

Given the products of adjacent cells, can you complete this Sudoku?

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?

Which pairs of cogs let the coloured tooth touch every tooth on the other cog? Which pairs do not let this happen? Why?

Arrange the four number cards on the grid, according to the rules, to make a diagonal, vertical or horizontal line.

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?

How many zeros are there at the end of the number which is the product of first hundred positive integers?

Given the products of diagonally opposite cells - can you complete this Sudoku?

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?

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?

The clues for this Sudoku are the product of the numbers in adjacent squares.

Can you make lines of Cuisenaire rods that differ by 1?

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. . . .

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.

In how many ways can the number 1 000 000 be expressed as the product of three positive integers?

An environment which simulates working with Cuisenaire rods.

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?"

Got It game for an adult and child. How can you play so that you know you will always win?

Find the largest integer which divides every member of the following sequence: 1^5-1, 2^5-2, 3^5-3, ... n^5-n.

Gabriel multiplied together some numbers and then erased them. Can you figure out where each number was?

Follow this recipe for sieving numbers and see what interesting patterns emerge.

Can you explain the strategy for winning this game with any target?

Substitution and Transposition all in one! How fiendish can these codes get?

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?

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?

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?

The number 12 = 2^2 × 3 has 6 factors. What is the smallest natural number with exactly 36 factors?

Factors and Multiples game for an adult and child. How can you make sure you win this game?

Can you find any perfect numbers? Read this article to find out more...

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.

Find the highest power of 11 that will divide into 1000! exactly.

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?

Ben, Jack and Emma passed counters to each other and ended with the same number of counters. How many did they start with?

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.

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...

Imagine we have four bags containing a large number of 1s, 4s, 7s and 10s. What numbers can we make?

Play this game and see if you can figure out the computer's chosen number.

Can you find a way to identify times tables after they have been shifted up or down?

Can you work out how many lengths I swim each day?

I'm thinking of a number. My number is both a multiple of 5 and a multiple of 6. What could my number be?

I added together some of my neighbours' house numbers. Can you explain the patterns I noticed?

A three digit number abc is always divisible by 7 when 2a+3b+c is divisible by 7. Why?

What is the largest number which, when divided into 1905, 2587, 3951, 7020 and 8725 in turn, leaves the same remainder each time?