Monday, January 30, 2006
Today, on a homeschooling discussion board, I posted this complaint, er ... question:
I'm looking for some real life applications for my daughter for multiplying fractions ... something she can grasp, something beyond the very unreal examples in math books.
Here's how my daughter and I would both respond to the following problem in her math book:
"Larry ordered 3/8 of a pizza. He gave Pat 1/3 of his pizza. How much of a pizza did Pat get?"
She and I would both say this sort of thing:
"Do you think Pat is a guy? Or his wife? And why would someone order 3/8 of a pizza? That's ridiculous. I might order by the slice, but never in fractions. Pat must be a guy friend, because Larry certainly would give his own wife more than 1/3 of 3/8 of a pizza. Are you hungry? Let's get something to eat. Then maybe we could write a story about a hungry mother and daughter who abandon math, join forces to open a pizzeria and hire people to do all the stuff that makes them lapse slowly into comas ... i.e., the measuring, the math ...."
... I do think doubling or tripling is easy for her to see, but what we're missing is when will one use things like this:
1/3 x 3/8
3/4 x 2/3
4/21 x 7/9
and the countless other examples in any math book? What's the point of these? Who uses them?
... When in real life do we do this? When in life do I do this? Or shall we chalk it up to "needed to move on and pass SATs down the road ...."
As you can see, we're big on the living books, literature, history, and oohing and aahhing over science that involves life forms, but the math? Not so much.
The only things I've been able to figure out in answer to my question:
I can think of instances in which we'd need to divide a fraction, and since in the universe of math we divide by inverting and multiplying, we just have to know how to do the pluttification before we can do the division.