I've been grading calculus exams this week, and even though my students did quite well overall there were a couple of errors that I see every semester. Errors that make mathematicians' heads explode.

A function machine is a way of writing rules using a flow diagram. The equation \(3j - 6 = 9\) can be shown on a function machine by writing out the functions that have been applied to \(j\) in the ...