Consider the set S n of all rearrangments of the numbers 1,2,3,...,n. We may represent each rearrangement in S n by diagrams like the ones below, where we use oriented strings to indicate where each ...

You don’t have to be born with math skills; solving problems is a matter of studying and motivation. That may not seem like such a surprise, but it’s become easy to say ‘I just can’t do math.’ While ...