MATHCO is a motivating series of audiovisual and print materials designed to overcome the negative effects of sex bias and stereotyping on the attitudes, interests, and aspirations of girls toward mathematics and mathematics-related careers. The materials teach mathematics skills, demonstrate relationships between mathematics and other subjects, and provide exposure to mathematics-related careers. They are useful for boys as well as girls at the pre- and early-adolescent stage; they are both multiethnic and nonsexist in text and illustrations. Module 5 considers the relationship between science and mathematics. The ability to make careful observations is stressed. Following the audiovisual script, 14 activities involving classification, levers, noise, archaeological digs, air pollution, and litter, among other topics, are considered, with activity worksheets for each. (MNS)