Last week I posted Myths About Math. This is the second installment in my series of posts busting those myths. Mind Over Math's 7th myth was "It's bad to count on your fingers."
When I'm teaching I often think out loud. Talking about powers, I often count on my fingers: 2 (first finger) times 2 (second finger) is 4, times 2 (third finger) is 8, (fourth finger) 16, (fifth finger) 32. I know my students haven't memorized powers of 2, so the quickest way to figure them is to multiply repeatedly by 2 and keep track on our fingers.
Of course, students who haven't memorized their times tables, but who add well, can do the same. Fives are the easiest: 7 times 5 is... 5, 10, 15, 20, 25, 30, 35 (and we stop when our 7th finger pops up).
So counting on our fingers is useful any time we're trying to figure something that needs a repeated step. Perhaps the thing I want to figure can be memorized. But if I haven't memorized it yet myself, the most efficient way to figure it will likely involve fingers.
Learning math is a process. Young children can add 2 blocks and 3 blocks by touching each one and finding the total. At some point, they learn that they can imagine the blocks and count them by touching a different finger for each one. And those fingers are one of the first steps towards the power math has to generalize.
What happens when a person becomes embarrassed about counting on their fingers? If they still want to think, they'll hide it. That's the better option. A worse option happens to way too many students: This may be the point where discomfort with not living up to someone else's expectations makes them give up on math, and then they just guess.
What do you think?