Studies report that U.S. students rank among the lowest in the area of mathematical knowledge of all industrialized countries. Schools in the United States are producing graduates ill-prepared to be successful at jobs which require mathematical competency. To increase mathematical understanding, this study examined the inclusion of writing in mathematics teaching. The study was based on theoretical foundations of constructivism as an effective teaching strategy. This quasi-experimental study used a nonequivalent control group design and compared the achievement of eighth-grade students in mathematics who participated in writing activities with a control group. A pretest and posttest were administered to track their progression of growth over an 18-week period. All data were statistically analyzed using an independent "t" test and an ANOVA. Results indicated that the two groups did not statistically differ on mathematics achievement. The overall data were found to have positive benefits for students and educators. Students received the positive benefit of self-reflected learning. Educators were positively benefited with a view of the students' critical thinking skills. Recommendations include continued research of best teaching practices in mathematics and providing an opportunity for teachers to engage in collegial discourse to learn, share, and plan for writing activities in math. This study contributes to positive social change by increasing the awareness of the need for math literacy in a society that depends on mathematics competency for economic advancement. The results of this study could help educators improve mathematics instruction resulting in increased math performance among U.S. students. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]