Divisibility
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articleDivisibility Tests
This article explains various divisibility rules and why they work. An article to read with pencil and paper handy.
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problemFavouriteTake Three From Five
Caroline and James pick sets of five numbers. Charlie tries to find three that add together to make a multiple of three. Can they stop him?
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problemFavouriteBig Powers
Three people chose this as a favourite problem. It is the sort of problem that needs thinking time - but once the connection is made it gives access to many similar ideas.
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problemFavouriteBen's Game
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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problemFavouriteExpenses
What is the largest number which, when divided into these five numbers in turn, leaves the same remainder each time?
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problemFavouriteWhy 24?
Take any prime number greater than 3 , square it and subtract one. Working on the building blocks will help you to explain what is special about your results.
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problemKnapsack
You have worked out a secret code with a friend. Every letter in the alphabet can be represented by a binary value.
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