This study investigated two methods used to teach multidigit multiplication to fourth-grade students: the lattice method and the distributive method. Classes from four schools were randomly assigned so that the two treatment groups contained two each or urban, rural and inner city classrooms. A series of 15 lessons was prepared for each treatment and taught by the regular classroom teacher. A total of 264 students completed the study. Computational ability, speed of computation, understanding of the multiplication process, and attitude toward mathematics were all tested during this study. Experimenter-designed tests were used to assess computational skill and speed. The test for understanding of the multiplication process was a composite test using appropriate items from the Stanford Achievement Test and the Metropolitan Test. The Dutton Attitude Scale measured attitudes toward mathematics. Data were analyzed by analysis of variance. The groups using the lattice method were significantly more accurate and faster in computation than the distributive group, but there were no differences for understanding or attitudes. There were no interactions attributed to urban, rural or inner city groupings. (Author/JP)