Vectors are directed line segments. They are quite different from points, since they can be added, multiplied by a scalar or number, and subtracted. The arithmetic with vectors is very useful in Linear Algebra, and here we use it to describe various standard applications, including affine combinations of two vectors to describe all the points on a line segment or line determined by two vectors. We use vectors to prove that the diagonals of a parallelogram bisect each other, and that the medians of a triangle all meet.