A someone who followed courses in num op, I can say that yes, indeed, the math concepts are rather basic and not that hard to learn. BUT you have to be at ease with mathematical reasoning because many of the proofs are not that easy to understand, they involve quite a lot of small insights here and there. Nothing really hard, but your brain will definitely have to work to understand these.

So yeah, the necessary concepts to study that course are not much but you have to have a strong habit of thinking in maths to apply them. And that habit comes with a lot of practice...