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

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Work out Tom's number from the answers he gives his friend. He will only answer 'yes' or 'no'.

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

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Nine squares with side lengths 1, 4, 7, 8, 9, 10, 14, 15, and 18 cm can be fitted together to form a rectangle. What are the dimensions of the rectangle?

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Suppose we allow ourselves to use three numbers less than 10 and multiply them together. How many different products can you find? How do you know you've got them all?

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One quarter of these coins are heads but when I turn over two coins, one third are heads. How many coins are there?

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Nearly all of us have made table patterns on hundred squares, that is 10 by 10 grids. This problem looks at the patterns on differently sized square grids.

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In this activity, the computer chooses a times table and shifts it. Can you work out the table and the shift each time?

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Can you complete this jigsaw of the multiplication square?

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What do the numbers shaded in blue on this hundred square have in common? What do you notice about the pink numbers? How about the shaded numbers in the other squares?

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Can you see how these factor-multiple chains work? Find the chain which contains the smallest possible numbers. How about the largest possible numbers?

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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?"

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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.

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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.

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56 406 is the product of two consecutive numbers. What are these two numbers?

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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?

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

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How many different rectangles can you make using this set of rods?

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

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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.

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Investigate the smallest number of moves it takes to turn these mats upside-down if you can only turn exactly three at a time.

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

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

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

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I throw three dice and get 5, 3 and 2. Add the scores on the three dice. What do you get? Now multiply the scores. What do you notice?

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Can you fill in this table square? The numbers 2 -12 were used to generate it with just one number used twice.

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I am thinking of three sets of numbers less than 101. Can you find all the numbers in each set from these clues?

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The items in the shopping basket add and multiply to give the same amount. What could their prices be?

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What is the lowest number which always leaves a remainder of 1 when divided by each of the numbers from 2 to 10?

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The discs for this game are kept in a flat square box with a square hole for each. Use the information to find out how many discs of each colour there are in the box.

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Your vessel, the Starship Diophantus, has become damaged in deep space. Can you use your knowledge of times tables and some lightning reflexes to survive?

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There is a clock-face where the numbers have become all mixed up. Can you find out where all the numbers have got to from these ten statements?

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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...

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

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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.

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

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In this problem we are looking at sets of parallel sticks that cross each other. What is the least number of crossings you can make? And the greatest?

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

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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?

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An investigation that gives you the opportunity to make and justify predictions.

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Can you find different ways of creating paths using these paving slabs?

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

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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?

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Benâ€™s class were cutting up number tracks. First they cut them into twos and added up the numbers on each piece. What patterns could they see?

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Imagine a wheel with different markings painted on it at regular intervals. Can you predict the colour of the 18th mark? The 100th mark?

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Which is quicker, counting up to 30 in ones or counting up to 300 in tens? Why?

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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?

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The planet of Vuvv has seven moons. Can you work out how long it is between each super-eclipse?

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Does this 'trick' for calculating multiples of 11 always work? Why or why not?