Wyzant
Wyzant: Factoring Numbers
Never quite understood factors? This site explains it all. Review what a factor is and how to find it.
University of Cambridge
University of Cambridge: Nrich: Multiplication Squares
On this one page website sharpen your logic and multiplication skills while working on this challenge. The solution is available to double check your solution.
University of Cambridge
University of Cambridge: Nrich: What's Left?
On this one page website sharpen your logic and factor recognition skills while working on this challenge. The solution is available to double check your solution.