This study addressed the problem of promoting generalization of knowledge in people with mental handicaps, by presenting an approach based on the idea that certain cognitive representations of strategies and related concepts are common to solving a wide variety of problems. The surface context of these problems may vary considerably, but all will require the use of a common mental representation. The example used in the study was numerical evaluation, which is required in a wide variety of contexts including time telling, money skills, science, social numeric tasks, and graphic copying. Educable and trainable teen-aged students (N=13) were taught numeric evaluation skills using a guided discovery approach and then were found to be able to use their knowledge in a wide variety of situations. Numerical evaluation questions and generalization questions are appended. Includes eight references. (Author/DB)