University of Waterloo (Canada)
Wired Math: Primes and Prime Factors [Pdf]
Explore primes, prime factors, and composites using this collection of worksheets. Lots of detailed examples, interesting math facts, and colorful visuals. Acrobat Reader required.
University of Waterloo (Canada)
University of Waterloo: Cemc: Math Circles: Number Theory Ii [Pdf]
This learning exercise provides a series of problem-solving questions that require higher order thinking skills. Questions will include finding the greatest common divisor, and least common multiple.