Our Tax Dollars at Work

Posted on by Denise Gaskins

Well, the new year has come, and it’s time to start gathering up receipts and thinking about tax forms.

Would you like to know that our tax dollars are doing good in the world? The National Science Foundation has spent many millions developing and promoting “reform” math textbooks, with encouragement from the U.S. Department of Education. Surely our public schools will now rise out of the doldrums and surge ahead in mathematical achievement, right?

Try for yourself this problem from one of the more famous/infamous of the reform math textbooks:

Can you find the slope and y-intercept of this equation?

10 = x – 2.5

And then check out this editorial[editorial has disappeared] at edspresso.com. You’ll be amazed at the answer!

Update: Checking on back-links, I discovered that this page had gone AWOL, so I’ll give you the “answer” from the teacher’s manual. The “slope” is 1 and the “y-intercept” is -2.5, according to Connected Math. Unfortunately, this equation actually describes a vertical line (undefined slope) at x=12.5 (never touches the y-axis).

Doesn’t bode well for “CMP helps students and teachers develop understanding of important mathematical concepts…”

Finding the Limit

Posted on by Denise Gaskins

[Rescued from my old blog.]

Eldest dd had her first calculus lesson last night: derivatives. The teacher found the speed of a car at a given point by using the distance function, calculating the average speed over shorter and shorter time intervals. Dd summarized the lesson for me:

“If you want to divide by zero, you have to sneak up on it from behind.”

Of course, she understands you can’t really divide by zero, but I thought her tongue-in-cheek comment was a pretty good description of the process of finding the limit as delta-t approached zero.

Math Humor, and Some Copywork Resources

Posted on by Denise Gaskins

[Rescued from my old blog.]

I have been reading up on Charlotte Mason’s teaching style, and I plan to incorporate more copywork and dictation into our school program next year. Here are a few of my favorite funny quotes about math. (These would also make great blackboard quotes for a math classroom.)

Continue reading Math Humor, and Some Copywork Resources

So You Think You Know Calculus?

Posted on by Denise Gaskins

[Rescued from my old blog.]

Rudbeckia Hirta over at Learning Curves submits a great idea for a new TV blockbuster:

So You Think You Know Calculus?

I’ve read that Charlotte Mason used oral exams like this with her students, though of course without the pressure and sarcastic comments. I’d love to hear how this works in “real life.”

Continue reading So You Think You Know Calculus?