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Find all the triples of numbers a, b, c such that each one of them plus the product of the other two is always 2.
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Which rational numbers cannot be written in the form x + 1/(y + 1/z) where x, y and z are integers?
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To make 11 kilograms of this blend of coffee costs £15 per kilogram. The blend uses more Brazilian, Kenyan and Mocha coffee... How many kilograms of each type of coffee are used?
Age 14 to 16 Short Challenge Level:
In each row of the table, the third cell contains the sum of the contents of the first two cells.
In each column of the table, the third cell contains the sum of the contents of the first two cells.
This problem is adapted from the World Mathematics Championships
What total would you get if you added up the contents of all nine cells?
This problem is adapted from the World Mathematics Championships
You can find more short problems, arranged by curriculum topic, in our short problems collection.
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NRICH is part of the family of activities in the Millennium Mathematics Project.
NRICH is part of the family of activities in the Millennium Mathematics Project.