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Age 14 to 16 Short
Challenge Level


Roger picks two consecutive integers, one of which ends in a 5.

He multiplies the integers together and then squares the result.

What are the last two digits of his answer?





This problem is taken from the UKMT Mathematical Challenges.
You can find more short problems, arranged by curriculum topic, in our short problems collection.
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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