The purpose of this study was to investigate the effects of a web-based strategic, interactive computer application (Fun Fraction) on the ability of middle school students with LD, who have mathematics goals on their IEPs, to solve word problems with fractions and multiplication including two factors of a whole number (less than or equal to 4) and proper fractions. A multiple-probe single case research design across subjects was applied for the study. Three middle school students with learning disabilities participated in baseline, intervention, and maintenance test sessions over a 13-week period. Findings showed that there was an experimental effect for all three students, tested on their instructional probes; students' performance improved from baseline to intervention phases after receiving instruction through Fun Fraction. John and Alec reached the mastery level of 80% on two of the three review days. The level of change from baseline to intervention phases ranged from 28.67% to 68.89%. Even through there was no immediacy effect for John, the trend of his data (10.33) revealed a substantial growth in general. Additionally, the percentage of data showing improvement between baseline and intervention phases was 70% for Tiffany, 56% for John, and 100% for Alec. In particular, the improvement trend of Alec's data was statistically significant (Tau[subscript novlap] = 1, p < .05, CI 90% = .341<>1.659). All of them reached 80% accuracy percentage on their one-time maintenance tests. Regarding the three problem types of combine, partition, and compare for each representation and equation question, students struggled the most with combine representation questions and showed relatively better competence in compare equation questions. A learning-related social validity questionnaire and usability questionnaire indicated that students liked learning through Fun Fraction and recognized well the useful interaction design features embedded in Fun Fraction. Cognitive and metacognitive strategy questionnaires also indicated that students liked the represent strategy that allowed students to manipulate the rectangular area model, and students expressed positive views on the thinking process through metacognitive strategies embedded in Fun Fraction. / text