Better Extra Credit

Wednesday June 03, 2015

•  finite mathematics •  math education •  mathematics •  teaching •  UMGC • 

It’s from back in April, but Confessions of a Community College Dean has a great post on extra credit. This is a great outline for why I don’t like offering extra credit in my classes. It’s inherently inequitable. And very difficult to administer.

But I have a much larger problem with extra credit. In general, I don’t see how it is reasonable to give special credit to a student who merely did more of the same and didn’t demonstrate something special. But this summer, I tried something new.

Every time I teach 106, there’s a problem with students who engage in, let’s call it, inappropriate rounding. I usually spend a lot of the first two weeks telling my students to knock it off. The example that comes up every term is a problem from an old text book, when students were trying to run a compound interest equation with ten percent interest. When they divide by [latex]12[/latex] to get a monthly interest rate, they should get [latex]0.008\overline{3}[/latex]. Many students hit this and just make it [latex]0.008[/latex] or even [latex]0.01[/latex]. They end up off by hundreds of dollars at the end of the process, even if they did everything else right.

So I put together a four or five page minilesson on rounding, precision, and accuracy. I gave it to my students with some associated problems in our early summer session as an extra credit project due the end of the first week. It rocked. Importantly, when students would have rounding problems in discussion, my response was more or less, “Go do the EC project and then try again,” and everyone who followed up got the discussion right afterwards.

It’s only worth one percent of the class, so it highly unlikely to make a difference in anyone’s grade, but roughly two-thirds of my students attempted it. And in doing so, got the exposure to rounding problems we weren’t giving them some other way.

Image by Ken Teegardin / Flickr.