I went on the maths competition today, and there was an awesome task that went something like this:
You can only fill each letter with one positive normal number(1,2,3,4,5...), and circle of which the number can you get from the following:
So, same letters mean the same number and you can only use each same number only once(ie. If you decide to give K=1, that means no other letter can be 1)
I hope you understand it^^, enjoy solving this interesting 'puzzle'.
In mathematics, you don't understand things. You just get used to them.
Of course that result can be rigorously obtained, but who cares?
Combinatorics is Algebra and Algebra is Combinatorics.