Poll: the sum(7,9)

[J. Scott Saults]

Mark,

Indeed, this is an interesting and important question. I usually just retrieve the 'fact', but occasionally I count for certain sums that don't quickly come to mind, like 8+5 where I sometimes visualize five shapes, arranged like they are on a playing card, which I count up from 8. I remember coming up with this strategy in elementary school and using it only for certain sums that I had trouble remembering. It became a habit only for certain sums.

Although it is NOT my area of expertise, I know there has been a lot of research on this topic showing how there are individual, developmental, and cultural differences in mental arithmetic strategies. Some of this research has been done by a colleague of mine here at the University of Missouri, David Geary. A quick literature search also shows several recent, potentially relevant, articles by Jamie Cambell at the University of Saskatchewan. The locations of their web home pages are listed below. I could email you one of David Geary's articles (about strategy choices by children in simple and complex addition) if you contact me off-line.

David C. Geary, Chair and Professor, Department of Psychological Sciences, University of Missouri
http://www.missouri.edu/~psycorie/

Jamie Campbell,  Professor, Department of Psychology,University of Saskatchewan.
http://duke.usask.ca/~campbelj/work/Jamie_Campbelx.html

J Scott Saults
Department of Psychological Sciences
University of Missouri
Columbia, MO

>Date: Mon, 14 Mar 2005 20:38:57 -0800
>From: Mark Swindell <mdswindell at charter.net>
>I've got a question I'd be interested in hearing from as many of the 
>list as care to respond.
>It's this:  How do you mentally process simple addition/subtraction 
>facts?  What actually happens in your brain to elicit 16 when you hear 
>7+9? (for example)