One goal of most courses is to prepare students with basic knowledge and skills associated with the course content. Mastery learning can be a rewarding way to encourage greater student achievement by allowing students multiple attempts to demonstrate an understanding of course concepts. This may involve repeated submissions of individual assignments or selection from multiple assignments for a single submission. However, such techniques can be unsustainable in large classes where additional evaluation and grading taxes instructor time and resources. For two large enrollment (greater than 50) introductory level courses (PLS 366: Fundamentals of Soil Science; PLS 104: Plants, Soils, and People) offered in the Department of Agronomy at the University of Kentucky we implemented an adaptation of the mastery learning approach that encourages broader comprehension of course material and recognizes different learning styles, but does not require all students to redo all incorrect work. Instead, students are required to complete a minimum number of assignments, and then they are given the option to complete additional work that can be substituted for other completed assignments. In general, student perception of these grading systems were favorable; however, students did not seem to take full advantage of the available options because many did not choose to complete the additional assessments that could demonstrate further learning and be used to improve their course grade. (Contains 5 tables.)