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Pair Sums

Age 11 to 14
Challenge Level

Five numbers are added together in pairs to produce the following answers:
 

$0, 2, 4, 4, 6, 8, 9, 11, 13, 15$

What are the five numbers?
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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