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

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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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Katie and Will have some balloons. Will's balloon burst at exactly the same size as Katie's at the beginning of a puff. How many puffs had Will done before his balloon burst?

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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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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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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?

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Find the words hidden inside each of the circles by counting around a certain number of spaces to find each letter in turn.

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48 is called an abundant number because it is less than the sum of its factors (without itself). Can you find some more abundant numbers?

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Can you work out what step size to take to ensure you visit all the dots on the circle?

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

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This big box multiplies anything that goes inside it by the same number. If you know the numbers that come out, what multiplication might be going on in the box?

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You'll need to know your number properties to win a game of Statement Snap...

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Watch the video of this game being played. Can you work out the rules? Which dice totals are good to get, and why?

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Can you make square numbers by adding two prime numbers together?

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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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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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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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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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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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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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Can you complete this jigsaw of the multiplication square?

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

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

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

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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?

This article for primary teachers outlines why developing an intuitive 'feel' for numbers matters, and how our activities focusing on factors and multiples can help.

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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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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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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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Can you work out the arrangement of the digits in the square so that the given products are correct? The numbers 1 - 9 may be used once and once only.

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Number problems at primary level that may require resilience.

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Is it possible to draw a 5-pointed star without taking your pencil off the paper? Is it possible to draw a 6-pointed star in the same way without taking your pen off?

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

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Each light in this interactivity turns on according to a rule. What happens when you enter different numbers? Can you find the smallest number that lights up all four lights?

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

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

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There are eight clues to help you find the mystery number on the grid. Four of them are helpful but the other four aren't! Can you sort out the clues and find the number?

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Each clue in this Sudoku is the product of the two numbers in adjacent cells.

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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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Number problems at primary level to work on with others.