Though advanced age has made her eyesight mostly theoretical, Venerable Mom still maintains a lively interest in the affairs of the day, and we talk every week or so about something that's caught her roving mind. Her question of a few days ago was off her regular pattern: she called to ask me how to count backward from 100 by sevens. "100, 93, 86, 79, 72," I said, continuing until she insisted that I stop. "No, no," she said, "I don't need to know the numbers, I want to know how to do it quickly." I said, "Imagine that you're looking at a number line that shows all the numbers from 1 to 100 (my fourth-grade classroom had one). Then start at 100 and move 7 places to the left and call out the numbers as you go."
"That won't work," VM told me, "you know I can't see a thing." "No, Mother," I replied, "you don't have to see it; you just have to imagine it." She rejected the idea, and also quickly rejected arranging 100 dots in a 10-by-10 array and visualizing 7 dots at a time being removed.
"By the way, Mother," I asked, "why do you need to count backward by sevens?" She told me that it's part of the mental test that her physician gives her to see if her mind is functioning properly, and she wants to be able to score well. "I can't believe this, Mom," I told her. "You're asking me to help you cheat on a senility test?"
After a fit of laughter, she replied, "Well, that shows I haven't lost my mind yet."