I’ve been mashing up web resources for my College Algebra class this semester. For the most part, I stick to Khan academy videos because students tend to like them and the library is so extensive. On some topics, I’ve been pushed out onto the web to supplement. One of the best math video resources I’ve found on the web is MathTV. There are a couple of things I really like about it. One, videos are introduced by the problem not by the topic. I have noticed, when pushing my students to find web resources on their own, a huge block for them is coming up with the relevant search terms for the skill e.g. simplifying complex fractions. However, they are much better at recognizing when a problem is similar to the one they want to solve. Therefore, MathTV makes it easier/faster for them to find what they are looking for. The second reason I like MathTV is they have multiple explanations of the same problem by different tutors. Sometimes there is even a Spanish language option.
The frustrating thing is that I can’t link directly to a list of videos on a particular skill. You can see them altogether, but there isn’t a unique URL for that view. They have a playlist creation function on the website that didn’t work very well that is supposed to accomplish this. But even if it did, that is a lot more work than I want to do. It would be nice to copy the link for “absolute value equations” directly from my browser, and then paste it into my discussion system.
I was hanging out with my cousins in Boston and in conversation they referenced a dating convention I’d never heard of. Apparently you’re not supposed to date anyone less than half your own age plus seven. So if I’m 40 right now, half my age is 20, plus 7 is 27. I can’t date anyone younger than 27. Being a geek, I immediately thought cool function!
f(x)=1/2x+7, where x is my age; keeps one from creepiness
It is interesting that this also sets an upper bound on who I can date. If I date an older person, I can not be less than 1/2 his/her age plus seven. So that means I can’t date anyone older than seven less than my age times two.
g(x)=2(x-7)
I found a cool graph of both one’s upper and lower dating limits at Bellesouth.
I place $20 in a box.
So do you.
Now the box contains $40, and we both know it.
I sell the box to you for $30.
And we both walk away with a $10 profit.
Jay sent over a link this great problem. It’s from one of my favorite blogs Futility Closet. This is the perfect kind of problem to throw out in class…easy to remember and easy to think through in a few minutes. What’s lovely is that initially it seems so plausible and yet impossible that they both profit $10. It reminds me of a Nova show (embedded below) I was watching on neuroscientists studying magic. Most tricks rely on our visual system’s strong bias toward detecting and anticipating motion. I feel like this problem and ones like it trick our reason, possibly with the momentum of language? Whoa, that got deep! Better stop right there.
Here is a blog to watch. Scientific American is running a guest blog on it’s site by Bob Gruman called mhpoetica. It explores the world of mathematical poetry. Yes, there is a “world”.
I found a great Flickr photo group via Free Tech for Teachers. It is called Bad Maths, and is a place to post pics of the crazy math sometimes sees when shopping. Danny Nicholson, the groups admin, uses it in class as a warmup. There are some really good ones. Definitely worth a few chuckles.
