I guess that I've been so caught up in other things that I didn't even notice that last week was the Second Birthday of this blog, counting from the publication of the first Co-Medians strip. (The blog is older than that, but back then it was for my students, none of whom actually came here.)
I didn't even realize until Halloween was almost here. The Halloween comic was the third one.
So I had one of these moments yesterday when reviewing for a midterm, the kind where you realize that something obvious to you might not be obvious to them. There's a "teachbable moment" there, for me as well as them.
I wrote on the board:
What is the difference between these two phrases? "25% of the original price" "25% off the original price"
Forget the math for a moment and tell me in English.
The only difference is "of" and "off". That one letter "f" makes all the difference in the world in solving the problem. And they have all seen commercials for sales on TV. This is "Math in the Real World", which they're always asking about.
If something is 25% "of" the price, we're multiplying by .25. Or even better, we're dividing by 4. (Some of my high school freshmen didn't understand this connection between .25 and a quarter despite the number of times I talk money.)
If something is 25% "off" the price, we're still multiplying by .25, but that isn't the price we're paying. That's the price we're saving. That's the discount from the original price. (I made sure to say "from" instead of repeating "off" there.)
Different question. Different answer.
I was stressing the importance of reading the question and, more importantly, reading it carefully to make sure that you are aswering the question that is being asked.
And this was a teachable more for me as well because one of the review questions on the sheet had to do with Linda buying a $48 coat for 25% of the original price. The answer to the question, of course, was $12.
However, a student pointed out to me that $12 was not one of the choices. Linda hadn't bought a $48 coat at all. She spent $48 on a coat that had cost much more.
There was a spike in traffic the other day as someone (other than me) liked a comic enough to put it on StumbleUpon, reddit and digg. It's the first time something on reddit didn't get voted down to zero votes. Anyway, I was looking at the breakdown by country.
So I'm not Jerry Lewis.
(I do have decent numbers in Germany, so I could be David Hasselhoff if I work harder at it.)
Dateline: Stick-World! Women on rickety ladders and flying superheroes! They go together like peanut butter and chocolate in a candy store. Which, co-incidentally, is where we can find said woman, ladder and superhero as our story unfolds.
I'm still disappointed over New York 2012. So congratulations to Brazil, which is part of South America, which is represented by one of those five Olympic rings, despite never hosting the Olympics. (The World Cup, on the other hand, ...)
Dateline: Stick-World!The Late Edition How Late? A week late! If you were here last week, so were we, but no one thought to spread the word. Spread it like strawberry jam on toast. Mmmmmmmm, toast ....
For those of you trying to follow the Prologue of our epic adventure, here's the ending, on page 6.
When you're done with the prologue, click on the link and follow the exciting story!
Mr. Burke is a high school math teacher in New York as well as a part-time writer, and a fan of science-fiction/fantasy books and films.
He started making his own math webcomic totally by accident as a way of amusing his students and trying to make them think just a little bit more.
Unless otherwise stated, all math cartoons and other images on this webpage are the creation and property of Mr. Chris Burke and cannot be reused without permission.