The enVisionmath 2.0 curriculum was implemented by a medium-sized school district to improve achievement for all elementary students because the district felt that students were underperforming in mathematics. The belief of underperformance mirrors the performance of U.S. students on international measures. For instance, the performance of U.S. students compared to students from other nations on the TIMMS assessment, shows that U.S. students are performing at lower rates of proficiency than students from many other nations (Lim & Sireci, 2017; NAGB, 2018). In order to close this achievement gap, teachers require access to quality curriculum materials that are accurate, provide opportunities for students of all abilities engage in rigorous mathematics, and are comprehensive in nature (NCTM, 2000a; NMAP, 2008). A mixed methods study was conducted in order to achieve two goals. First, the curriculum components were compared to the recommendations of both the National Council of Teachers, a professional organization of mathematics educators and researchers, and to the recommendations of the National Mathematics Advisory Panel, a group formed by the U.S. Department of Education. Descriptive statistics and linear regressions were applied to the district results to determine if statistically significant progress could be documented after implementation of the product. Results were calculated for the following groups: all students, students receiving special education services, and students from low socioeconomic backgrounds. The subgroup of English Language Learners was too small, even at the district level, to provide reliable results. It was determined that the enVisionmath 2.0 curriculum aligns with the recommendations of the National Council of Teachers of Mathematics and the National Mathematics Advisory Panel. No statistically significant results were found for students after the use of the enVisionmath 2.0 curriculum; however, the skewed normal distribution showed trends to higher scores for the subgroups of grade 4 and grade 5 special education students and grade 5 students from low socio-economic backgrounds. No data for English Language Learners could be analyzed due to the low number of students taking the MAP and PARCC assessments. [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.]