Pyramidal N-gon
Age 14 to 16
ShortChallenge Level 
The base of a pyramid has $n$ edges. In terms of $n$, what is the difference between the number of edges of the pyramid and the number of faces?
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.
You may also like
Gnomon Dimensions
These gnomons appear to have more than a passing connection with the Fibonacci sequence. This problem ask you to investigate some of these connections.
Searching for Mean(ing)
If you have a large supply of 3kg and 8kg weights, how many of each would you need for the average (mean) of the weights to be 6kg?