This is an elementary introduction to polynomials.
http://www.purplemath.com/modules/polydefs.htm
This is an elementary introduction to multiplying polynomials.
http://www.purplemath.com/modules/polymult.htm
This first part of this site provides some practice polynomial terminology, and with working with polynomials. It has some nice links.
http://www.wtamu.edu/academic/anns/mps/math/mathlab/int_algebra/int_alg_tut25_poly.htm
This is an excellent site providing interactive practice with the binomial theorem.
http://www.themathpage.com/aPreCalc/binomial-theorem.htm
An interactive version of Pascal’s Triangle.
https://www.transum.org/Maths/Activity/Pascals/Patterns.asp