University of Cambridge
University of Cambridge: Nrich: Two Primes Make One Square
On this one page website sharpen your logic, prime numbers and square numbers skills while working on this challenge. The solution is available to double check your solution.
University of Cambridge
University of Cambridge: Nrich: A Conversation Piece
On this one page website sharpen your logic, division and prime number recognition skills while working on this challenge. The solution is available to double check your solution.
Purple Math
Purplemath: Lcm & Gcf
Purplemath shows an easy and orderly way to determine the GCF and LCM of any two numbers. Even large numbers won't be a challenge with this method.