McGraw Hill
Glencoe: Self Check Quizzes 2 Prime Factorization
Use Glencoe's Math Course 2 randomly generated self-checking quiz to test your knowledge of prime factorization. Each question has a "Hint" link to help. Choose the correct answer for each problem. At the bottom of the page click the...
Shodor Education Foundation
Shodor Interactivate: Factorize
This Shodor site gives a brief explanation of factorization, and it allows you "to find all of the factorizations of a given number and then draw the product as the area of a rectangle on a grid."