This study examined the effects of the (Singapore) Model Method on elementary pre-service teachers' understanding fractions and attitudes toward teaching and learning mathematics. In particular, this study focused on fraction operation concepts in solving word problems. The study involved thirty-four elementary pre-service teachers enrolled in two sections of mathematics content and methods courses in the Teacher Education Program in a Midwestern public university. This study used quantitative data from an experimental design using an instructional intervention (Model Method). The instruments for data collection included a demographic questionnaire, mathematics attitude survey, fraction computation test, and fraction word problem test. To attain additional information for the instructional intervention and to verify the findings of the quantitative data, open- ended interviews were conducted. Quantitative data were analyzed using descriptive and inferential statistical methods, including MANOVA, ANCOVA and correlation analysis. The treatment group received six intensive lessons to learn fraction operation from word problems with a focus on the Model Method while the control group had traditional lessons with the same topics and materials. The findings show that using the Model Method in teaching fraction operation concepts helps the pre-service teachers to improve their conceptual understanding in solving word problems. After the Model Method instruction, an attitude survey and interviews were used and indicated that the experimental group had more positive attitudes and increased confidence and liking toward teaching and learning mathematics than the control group. Furthermore, the correlation analysis shows that the correlation between the pre-service teachers' fraction knowledge in solving word problems and computational problems was strong. This result indicates that higher conceptual knowledge can predict a higher level of procedural knowledge in fraction operations. The findings suggest that the Model Method is an effective teaching method to enhance students' fractional knowledge in learning problem-solving.