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My briefcase has a three-number combination lock, but I have forgotten the combination. I remember that there's a 3, a 5 and an 8, but not what order they go in.
How many possible combinations are there to try?
Six new homes are being built! They can be detached, semi-detached or terraced houses. How many different combinations of these can you find?
This challenge is to design different step arrangements, which must go along a distance of 6 on the steps and must end up at 6 high.
Suppose there is a train with 24 carriages which are going to be put together to make up some new trains. Can you find all the ways that this can be done?