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 $y=ax^2+bx+c$ 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?

## Top Trumps

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, acb²-4ac) 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, ab 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.