Khan Academy: Pre-Calculus
Khan Academy

The Precalculus course, often taught in the 12th grade, covers Polynomials; Complex Numbers; Composite Functions; Trigonometric Functions; Vectors; Series, Conic Sections, Probability and Combinatorics.

Khan Academy: Linear Algebra
Khan Academy

Learn linear algebra for free—vectors, matrices, transformations, and more.

NRICH: Vector Racer
NRICH (University of Cambridge)

Who can get round in the fewest moves?

GeoGebra: Mystery Scalar and Vectors Investigation
GeoGebra

Two vectors and a mystery scalar: Discovery Learning Investigation