The Spreadsheets Across the Curriculum (SSAC) library consists of activities to reinforce or teach quantitative literacy or mathematical concepts and skills in context. Each SSAC “module” consists of a PowerPoint presentation with embedded Excel spreadsheets. Each student works through a presentation, thinks about the in-context problem, figures out how to solve it mathematically, and builds spreadsheets to calculate and examine answers.To assess the effectiveness of SSAC modules, I surveyed Eckerd College undergraduates in two separate studies. Two undergraduate research assistants and I generated pre- and post-tests for 10 SSAC modules. We hired 21 undergraduates who conducted 62 individual module assessments during their free time in exchange for modest stipends. To complement this initial study, 12 students assessed three modules in the context of an upper-level geology course. In both the individual and in class experiments, students with a wide variety of academic interests and expertise showed improvements in quantitative and Excel skills.Based on my experiences, I recommend that instructors wishing to use SSAC modules carefully match student ability with module difficulty, use more than one module over the course of a semester, ensure that students have realistic expectations before starting, and facilitate student use in a supervised setting.