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Counting Factors

Is there an efficient way to work out how many factors a large number has?

Big Powers

Three people chose this as a favourite problem. It is the sort of problem that needs thinking time - but once the connection is made it gives access to many similar ideas.


Do you know a quick way to check if a number is a multiple of two? How about three, four or six?

Stamp Collecting

Age 11 to 14 Short Challenge Level:

Last week, Tom and Sophie bought some stamps for their collections.
Each stamp Tom bought cost him £1.10, whilst Sophie paid 70p for each of her stamps.

Between them they spent exactly £10.

How many stamps did they buy in total?

If you liked this problem, here is an NRICH task which challenges you to use similar mathematical ideas.
This problem is taken from the UKMT Mathematical Challenges.
You can find more short problems, arranged by curriculum topic, in our short problems collection.