Getting students to remember MC=MR

In any form of question where a knowledge of the profit-maximising level of output is required, it is amazing how often students forget the basic formula of MC=MR. I use the following method to help them learn (and remember) it.

My theory is that if they put a bit of work into discovering what the formula is, they are much more likely to remember it. I use the free stereogram creator to hide MC=MR in a graphic, print it out and then hand it out to the students, telling them that hidden in the picture is probably the most important formula of the year. They try like mad to figure out what it says and some are able to get it, and some never can. Regardless, they remember it as “hidden treasure” and every time they go to draw a graph they recall what they saw (or in a number of cases, what others have told them is there)!

Although I hand out my write-on notes on a topic basis, I actually go to the trouble of inserting a colour page with the graph into the otherwise black and white copy they receive - this means it is there when they want to study and I will often see them in class having another look at it a few days later to check if they can still see it.