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Double Digit

Choose two digits and arrange them to make two double-digit numbers. Now add your double-digit numbers. Now add your single digit numbers. Divide your double-digit answer by your single-digit answer. Try lots of examples. What happens? Can you explain it?

Not a Polite Question

When asked how old she was, the teacher replied: My age in years is not prime but odd and when reversed and added to my age you have a perfect square...

Whole Numbers Only

Can you work out how many of each kind of pencil this student bought?

The Patent Solution

Age 11 to 14
Challenge Level

This is quite a challenge and it is really a magic square in disguise! Here is one solution and another similar puzzle for you to try. You may like to study the articles Magic Squares and Magic Squares II.

Patent Solution solution

Patent Solution Solution

Another Patent Puzzle - again the magic total is 132

The following puzzle comes from The Ultimate Book of Number Puzzles by Kenneth Kelsey published by The Cresset Press 1992, ISBN: 0 09 177204 4.

Another Patent Puzzle