Here are 7 mistakes. There represent all of the variety of mistakes from a selection of 36 students. The first two mistakes were repeated by several students, but the last 5 were unique in the sample.

Which of these mistakes would you predict? Which ones surprise you? Can you make sense of them all?

Why would $2m \times m^{2} = 3m^{2}$? Or $2m^{2}$?

This mistake was brought to you by the letters M, A, R, Y, B, O, U, R, A, S, S, and A. You can follow her on twitter and on her blog.