from an MAA blog posting: Service-Learning and Making a Difference, a guest post by Karl-Dieter Crisman, Friday, July 11, 2014.    Some math examples he is familiar with.

+Analyzing energy use and sustainability practices on campus (quantitative reasoning)

+Assessing volunteer versus state-provided aid in a local fire (intro statistics)

+Helping local American Diabetes Association focus fundraising (finite math)

+Tutoring high school precalculus students (calculus)

+Creating math fun fair games (upper-level math and math ed)

+Designing a new layout for a food pantry (upper-level modeling)

+Providing feedback on cash flow for a local non-profit (upper-level modeling)

+Analyzing (scrubbed) freshman orientation data (upper-level math/stats)

+Running a math camp for middle-schoolers (graduate students)

see the posting at:

http://maamathedmatters.blogspot.com/2014/07/service-learning-and-making-difference.html