Having just spent a large chunk of my afternoon battling with Moodle’s quiz functions, fortunately I also came up with something a little more fun, interactive and actually quite challenging: quadratics top trumps.
Starter for 10
Here is a sketch of the graph for certain values of a, b and c:
- Is a positive, zero or negative?
- Is b positive, zero or negative? (Careful!)
- Is c positive, zero or negative?
- Is ac positive, zero or negative?
- Is b²-4ac positive, zero or negative?
I’ve written up a few more details in this Top Trumps Powerpoint (sorry but the graphs are a little small and uninspiring – perhaps someone is willing to tart them up a bit?!). Essentially, students play in pairs and try to pick a property (a, b, c, ac, b²-4ac) that they hope will beat their opponent. (Positive beats Zero beats Negative.)
Starters and Variations
In the Powerpoint, I mention a couple of possible starter activities to precede the game:
- Provide students with the same starter as in the blog post.
- Ask the students to sketch a quadratic for which, say, a, b and c are all negative.
- Try to limit the students from always choosing a or c – perhaps require them to have used all 5 different properties before they can repeat a choice.