## Archive for April 15, 2016

### Spreadsheets as an intuitive approach to variables: I don’t buy it

A piece in The Guardian (linked by Deepak Kumar on Facebook) described how Visicalc became so popular, and suggests that spreadsheets make variables “intuitive.” I don’t buy it. Yes, I believe that spreadsheets help students to understand that a value can change (which is what the quote below describes). I am not sure that spreadsheets help students to understand the implications of that change. In SBF (Structure, Behavior, Function) terms, spreadsheets make the structural aspect of variables visible — variables vary. They don’t make evident the behavior (how variables connect/influence to one another), and they don’t help students to understand function of the variable or the overall spreadsheet. If we think about the misconceptions that students have about variables, the varying characteristic is not the most challenging one.

The Bootstrap folks have some evidence that their approach to teaching variables in Racket helps students understand variables better in algebra. It would be interesting to explore the use of spreadsheets in a similar curriculum — could spreadsheets help with algebra, too? I don’t expect that we’d get the same results, in part because spreadsheet variables don’t look like algebra variables. Surface-level features matter a lot for novices.

Years ago, I began to wonder if the popularity of spreadsheets might be due to the fact that humans are genetically programmed to understand them. At the time, I was teaching mathematics to complete beginners, and finding that while they were fine with arithmetic, algebra completely eluded them. The moment one said “let x be the number of apples”, their eyes would glaze and one knew they were lost. But the same people had no problem entering a number into a spreadsheet cell labelled “Number of apples”, happily changing it at will and observing the ensuing results. In other words, they intuitively understood the concept of a variable.