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Double Digit

Choose two digits and arrange them to make two double-digit numbers. Now add your double-digit numbers. Now add your single digit numbers. Divide your double-digit answer by your single-digit answer. Try lots of examples. What happens? Can you explain it?

Whole Numbers Only

Can you work out how many of each kind of pencil this student bought?

The Patent Solution

A combination mechanism for a safe comprises thirty-two tumblers numbered from one to thirty-two in such a way that the numbers in each wheel total 132... Could you open the safe?

Not a Polite Question

Age 11 to 14 Short
Challenge Level

When asked how old she was, the teacher replied:

My age in years is not prime but odd
and when reversed and added to my age
you have a perfect square.

Or you can reverse and subtract, and
again you have a perfect square.


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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