Have you ever asked students to solve 12.6 x 10, and they respond that the answer is 12.60? I have, many times. Students who do this apply a pattern that works when they multiply whole numbers by 10—they tack on a zero to the end of the number they’re multiplying. But then they apply the same pattern when working with decimals. What can we do?
My friend Ann sent me an email about her unsettling experience at the supermarket deli counter. Ann has never felt particularly confident with her math ability, and I was pleased (and amused) that she asserted herself in this situation. Also, Ann’s comment to me about the work we face as math teachers rang true.