Midterms are going back this week. Before you return yours, try sorting the stack by question instead of by student.

When a lot of students give the same wrong answer, it is not random. It tells you which step broke, and that is the step to rebuild before the class moves on.

Today's Teaching Day session turns that into one page you can post the same day the grades go back: a short glossary, one worked example with the reason beside each step, and three practice problems.

Question for today, and one line is plenty: what was the most common wrong answer on your midterm this term?