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Sue from CBEC Basingstoke sent the following explanation to the first question:

** X ** = 4876
If you write 4876 as a product of prime factors you get 2 x 2 x 23 x 53
From this you need to find two, two digit numbers that use the digits 2, 3, 5 and 9
This has to be 2 x 2 x 23 = 92 and 53

We also received correct solutions from Jenny, Greenian, Rachael, Jacqui and Sam, from The Mount School, and Debbie from Forres Academy. Well done to you all.

53 x 92 = 4876
62 x 87 = 5394

24 x 57 = 1368
58 x 64 = 3712
52 x 34 = 1768

We'd like to hear from anyone who would like to explain how they solved these problems.
We are always interested in the reasoning that has helped you reach your solutions.


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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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