This study investigated the effects of single and multiple window presentation on achievement, instructional time, window use, and attitudes of fourth grade students during computer-based instruction. A total of 127 fourth grade students, classified as high and low ability, completed a computer-based mathematics lesson and a delayed posttest. High ability students answered more quiz problems correctly during the lesson than low ability students. Students in the multiple window treatment answered more practice problems correctly than students in the single window treatment. High ability students scored significantly higher on the posttest measures of verbal information, rule use, and problem solving. Students in the single and multiple combination treatment and students in the multiple window treatment kept the symbols window visible significantly longer than students in the single window treatment. High ability students accessed the symbols window significantly less than low ability students. Multiple window presentations may assist students in tasks where more than one source of information is needed to complete a problem.