Working systematically
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problemPair Sums
Five numbers added together in pairs produce: 0, 2, 4, 4, 6, 8, 9, 11, 13, 15 What are the five numbers?
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problemCoins
A man has 5 coins in his pocket. Given the clues, can you work out what the coins are?
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problemDistinct in a Line
This grid can be filled so that each of the numbers 1, 2, 3, 4, 5 appears just once in each row, column and diagonal. Which number goes in the centre square?
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problemAlmost Constant Digits
How many 10-digit numbers containing only 1s, 2s and 3s can you write?
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problemKangaroo Hops
Weekly Problem 11 - 2011
Kanga hops ten times in one of four directions. At how many different points can he end up? -
problemThe Best Card Trick?
Time for a little mathemagic! Choose any five cards from a pack and show four of them to your partner. How can they work out the fifth?
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problemSeasonal Twin Sudokus
This pair of linked Sudokus matches letters with numbers and hides a seasonal greeting. Can you find it?
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