Get up to speed with algorithms
I wouldn't have said they were algorithms per se, more a collection of transformations.

If you want to get a theoretical viewpoint on monads, I'd suggest picking up a category theory textbook. You don't need to do "3 years of maths" to understand one, just some set theory (probably) and some dedication.

On the other hand, if you'd prefer a practical handle, I'd learn the Haskell programming language, which uses monads extensively to represent certain types of side-effects. "Learn You a Haskell" is very good. Try and avoid the infamous "monad tutorials" which inevitably over-simplify in order to produce an analogy. I think just reading the monad typeclass, then looking at examples is probably the best advice.