The Bad and the Ugly #1
I thought I should share some of the things that surprise or enrage me. Clearly, I'm thinking here of mathematical strategies or resources that reinforce errors, not political, ethical or world issues.
Take, for example, the mathematical misconception that a square is somehow not a rectangle. In many quarters this is a very strongly held idea. An idea, that (by any mathematical definition) is wrong. However, it's easy to see how this error is reinforced...
Here's a poster spotted in a school only a few days ago:
Obviously, from the information presented here, a square could never be part of the set of objects we call rectangles! Bad, bad poster.
I didn't scream, or tear it down (yes, that was my first thought), but I did discuss it with the teacher. It now takes pride of place as the first of our 'Bad and Ugly' items.
If you've spotted anything that is equally erroneous and annoying feel free to moan about it in the comment box below. I'd love to hear your thoughts.