If researcher David McArthur of the Rand Corp. has his way, teachers of elementary algebra will soon get special assistants capable of tutoring students who are having difficulty grasping the subject.

However, the special assistants are not of the human variety; McArthur calls them computer tutors.

McArthur and fellow researcher John Hotta plan to test at least six of the tutors in classrooms at Santa Monica High School this September. The two developed the computer-based tutorial with the help of a $500,000 grant from the National Science Foundation in Washington. Designed to help students who are weak in the fundamentals, the tutorial takes pupils through algebra problems step by step, showing how the mathematical problems are solved and where a student's mistakes lie. Unlike many modern computer programs with colorful graphics and designs, the computer tutorial sends a simple signal whenever a correct answer is given, McArthur said.

"There are no bells and whistles going off," he said. "We want to motivate students to learn the lessons by appreciating their own sense of competitiveness."

To prepare himself for a return to basic algebra, McArthur spent several months in Santa Monica High School's algebra classes, where the failure rate among students is 50%, according to math teacher Gretchen Davis, a consultant for the tutor program. Davis welcomed McArthur to her class.

"Having another adult in the class helped relieve a lot of the frustration for beginning students," she said. "He worked with kids on a one-to-one basis. He analyzed the errors the kids make in the exams and then used the information to design the program."

McArthur said is acquired useful information in the classroom. "I had forgotten what the simple errors were that beginning students make, so I had to go back and become a beginner again," he said.

Rand also hired eight algebra students at $5 an hour to visit its computer lab to help design the program. Some were hired because they were doing poorly in math, but all showed improvement after working with the tutorial, McArthur said.

The experience "made me feel like a pioneer," said Andy Blumberg, a 16-year-old who was hired to work with students stymied by beginning algebra. "It was great to be one of the people helping to find the bugs in the system that could one day help many students who are having trouble."

McArthur has been a researcher for Rand since shortly after earning his doctorate in computer science and psychology from the University of Michigan in 1980. Before working on the computer tutorial program, he helped develop language for the computer simulation of war games. He said he prefers his present work because it is a "closed world defined by the laws of arithmetic."

McArthur said that the computer program "is nothing more than a smart algebra tutor that is capable of helping students improve their understanding of algebra at a time when math skills are declining and there is a shortage of math teachers."