Labahn, GeorgeLank, EdwardMarzouk, MiretteBunt, AndreaMacLean, ScottTausky, DavidChristine Alvarado and Marie-Paule Cani2014-01-282014-01-282008978-3-905674-07-11812-3503https://doi.org/10.2312/SBM/SBM08/143-150Current generations of computer algebra systems require users to transform two dimensional math expressions into one dimensional strings, to master complex sets of commands, and to analyze lengthy output strings for relevant information. MathBrush is a system, designed based on research in education pedagogy, that provides a pen-based interface to many of the features of computer algebra systems. We describe relevant work in education pedagogy as a motivation for MathBrush's design. We highlight aspects of MathBrush that are unique from other contemporary pen-math systems. Finally, we present the results of a thinkaloud evaluation of the MathBrush system. Together, these observations validate aspects of the current design of MathBrush, suggest areas for refinement, and inform the design of future pen-math systems.Categories and Subject Descriptors (according to ACM CCS): G.4 [Mathematical Software]: User interfaces