This research focuses on a dual mediation model designed to describe the learning process of sixth grade students practicing mathematics to improve Mathematics Operation Proficiency while experiencing different forms of feedback. The variables of interest in this study are the predictor variable feedback type, the mediating variables of Affective and Cognitive Engagement and the outcome variable of Mathematics Operations Proficiency. Mathematics Operations Proficiency was measured via standardized gain scores derived from Mathematics Pre-tests and Posttests. Cognitive Load Theory, Cognitive Information Processing Theory, Engagement Theory, and a model of the effects of feedback were used to develop the dual mediation model used in this research. The results suggest that feedback type significantly affects neither Mathematics Operations Proficiency nor Cognitive Engagement. Furthermore, the model specified does not fit the data, according to the following measures of model fit: [k (superscript 2] test of goodness of fit, the SRMR, the RMSEA, and the PNFI. Factors such as measurement quality, sample size, Common Core Mathematics Standards selected by teacher, the level of cognitive complexity of the items used, the amount time spent preparing for practice, the types of activities spent preparing for the practice, the implementation of the research, and the effects of the COVID19 pandemic on society as a whole and the recruited subjects in particular are all worth consideration in the interpretation of the lack of fit of the model and data collected. [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.]