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Number Detective

Follow the clues to find the mystery number.

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Red Even

You have 4 red and 5 blue counters. How many ways can they be placed on a 3 by 3 grid so that all the rows columns and diagonals have an even number of red counters?

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Prime Magic

Place the numbers 1, 2, 3,..., 9 one on each square of a 3 by 3 grid so that all the rows and columns add up to a prime number. How many different solutions can you find?

Sets of Numbers

Age 7 to 11 Challenge Level:

You could list all the properties of each number as a start.
Can you see some numbers which have the same property?