CK-12 Foundation
Ck 12: Vector Sum and Difference
[Free Registration/Login may be required to access all resource tools.] Looks at finding the direction and magnitude of vectors and breaking vectors into component parts.
National Council of Teachers of Mathematics
The Math Forum: Vector Addition: Algebra
Illustration and description of how to add vectors using algebra.
Wolfram Research
Wolfram Math World: Math World: Vector Addition
Defines vector addition and gives the algebraic notation for adding vectors. Includes a graphic and links to additional information.