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.

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

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 relationship between the number of dots on the circle and the number of steps that will ensure that all points are hit?

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.

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...

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

Here is a Sudoku with a difference! Use information about lowest common multiples to help you solve it.

A game in which players take it in turns to choose a number. Can you block your opponent?

A collection of resources to support work on Factors and Multiples at Secondary level.

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?

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

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

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

Imagine a machine with four coloured lights which respond to different rules. Can you find the smallest possible number which will make all four colours light up?

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?

When the number x 1 x x x is multiplied by 417 this gives the answer 9 x x x 0 5 7. Find the missing digits, each of which is represented by an "x" .

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

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?

The flow chart requires two numbers, M and N. Select several values for M and try to establish what the flow chart does.

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

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?

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 coincidence?

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

The triangle OMN has vertices on the axes with whole number co-ordinates. How many points with whole number coordinates are there on the hypotenuse MN?

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

How many numbers less than 1000 are NOT divisible by either: a) 2 or 5; or b) 2, 5 or 7?

Great Granddad is very proud of his telegram from the Queen congratulating him on his hundredth birthday and he has friends who are even older than he is... When was he born?

You are given the Lowest Common Multiples of sets of digits. Find the digits and then solve the Sudoku.

Here is a machine with four coloured lights. Can you develop a strategy to work out the rules controlling each light?

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

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.

Find the number which has 8 divisors, such that the product of the divisors is 331776.

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

What is the smallest number of answers you need to reveal in order to work out the missing headers?

15 = 7 + 8 and 10 = 1 + 2 + 3 + 4. Can you say which numbers can be expressed as the sum of two or more consecutive integers?

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...

A and B are two interlocking cogwheels having p teeth and q teeth respectively. One tooth on B is painted red. Find the values of p and q for which the red tooth on B contacts every gap on the. . . .

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

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

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

Can you find any two-digit numbers that satisfy all of these statements?

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

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?

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

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

Here is a chance to create some Celtic knots and explore the mathematics behind them.