See the Light

    Age 7 to 14
    Challenge Level

    I've thought of a rule.

    Numbers that obey my rule will light up the light.

    Try entering some numbers.

    Can you determine the rule?






     



     


    This activity is featured in the second half of Alan Parr's article Rocking Chairs, Railway Games and Rayboxes.
    The NRICH Project aims to enrich the mathematical experiences of all learners. To support this aim, members of the NRICH team work in a wide range of capacities, including providing professional development for teachers wishing to embed rich mathematical tasks into everyday classroom practice.
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    NRICH is part of the family of activities in the Millennium Mathematics Project.