I preparing to study electrical engineering with Khan Academy but some of the links are wrong, right now I on “Vectors, vectors addition” and the link sends me to the wrong unit where is no vectors addition, but I have found two units with the right unit but one of them is just algebra and the other one is precalculus because of that they’re a bit different and I don’t know witch one I should learn. Precalculus version: https://www.khanacademy.org/math/precalculus/x9e81a4f98389efdf:vectors Algebra version: https://www.khanacademy.org/math/algebra-home/alg-vectors