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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?

Divisible Digits

Age 11 to 14 Short Challenge Level:

I wrote down a 4-digit number that was divisible by 3, 4, 5 and 6, but I spilt a cup of tea on it and can only see the first two digits.

The first two digits are 95 (in that order). What were the last two?

This problem is adapted from the World Mathematics Championships
You can find more short problems, arranged by curriculum topic, in our short problems collection.