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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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Diagonal Trace

You can trace over all of the diagonals of a pentagon without lifting your pencil and without going over any more than once. Can the same thing be done with a hexagon or with a heptagon?

Light the Lights

Stage: 2 Challenge Level: Challenge Level:2 Challenge Level:2
Here is a machine with four coloured lights. Each light responds to a rule.

When you type in a number, lights go on if their rule is satisfied.
If the number satisfies more than one rule, then more than one colour will light up

Type in some numbers and see which lights you can switch on.







What is the smallest number which lights them all up?