Factors Game for Mac

From Polymath Love Software:

This is an on-screen version of a game often played on middle school chalkboards. From a list of consecutive integers the student may pick any integer that still has factors "in play." The student gets that value added to his/her score, and the computer is awarded the value of all the factors of the chosen number that are still "in play." The numbers selected are removed from play and the student chooses another number. Play continues until the student has no more legal moves. The computer then gets the value of all remaining numbers. The program is a good introduction to factors and primes.