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Special Numbers

Age 11 to 14
Challenge Level Yellow star
Secondary curriculum
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Try some different numbers to get a feel for the problem.
 
Special numbers all satisfy the following equation:
$$a + b + ab = 10a + b$$
 
 

Related Collections

  • Working Systematically - Lower Secondary

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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.

NRICH is part of the family of activities in the Millennium Mathematics Project.

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