Abstract
Electronic Homework was an intelligent tutoring system that runs on stand-alone computers [1] initially and is now migrated to the Web to provide on-line homework tutorial. The system contains a database of different sets of algebra problems from which learners can choose what sort of problems to practice. When a learner is solving a problem, the system diagnoses concurrently every step he/she does, and prompts and guides him/her back to the correct solution path once errors are detected [2] [3] [4] (Lee & Heyworth, 1997; Lee, 2001a; Lee, 2001b). Besides giving online tutorials, the system serves to collect students? errors for later analyses in order that the system can be improved (Lee & Heyworth, 1999).