Friday, September 30, 2005
Page 15
AT THE SIDEBAR (Column)
Decimals — What’s the Point?
By J’AMY PACHECO
It’s no secret that I am mathematically challenged. Once math gets beyond the “two plus two equals something like four, I think” stage, I’m usually lost.
When I dine out with friends and the time comes to split up the bill, I’m the one passing money. When people tell me it’s easy to calculate the tip by doubling the sales tax, I say that I’m morally opposed to doubling any tax, under any circumstances. Because I can’t.
I suspected I might be in some trouble when my daughter started learning multiplication and division facts in school. Her homework often included timed tests in which she had to do as many problems as possible – correctly. I could run the timer efficiently, but when it came time to check her work, I had to send her away while I used a calculator.
By the time she left third grade, I had a pretty fair grasp of single-digit multiplication. On a good day, I could do division, too, which I came to regard as multiplication done backward. If I could make it through that, I thought, maybe fourth grade wouldn’t present too big a challenge.
And then the homework started coming. I was calm when it was limited to questions like, “On Friday morning, the Kaplans drove from Battle Creek to Lansing. Then they drove 127 more miles. How many miles did they drive on Friday?”
A table listing mileage between cities in Michigan was provided, so arriving at the answer was not too difficult. But I think the teacher missed the really important part of the lesson, which is this: the Kaplans made eight driving trips on just one night’s homework. How on Earth can they afford the gasoline?
After that, the homework covered topics like rounding and greater-than-or-less-than. I felt myself treading mathematical water.
Then came the dreaded decimals.
At first, they weren’t too hard. The worksheets asked the students to write numbers like 1/10 or 78/1000 as decimals. It only took me about an hour to figure out how to do that. But things soon got more complicated.
A recent worksheet asked, for example, which was less: .02 or .020. My answer: How is anybody supposed to know that, and why should I care?
Unfortunately, that wouldn’t fit in the little space provided for the answer, so my little girl rejected it. She scratched her head and confessed she didn’t really understand that day’s lesson, and had assumed she could get me to explain during homework time. I was on the hook.
Taking my cue from a game show, I decided to phone a friend. She had been about to call me with the same question, so we decided to do a Google search to find out what effect that pesky zero had on the two.
I did the search, and learned that the U.S. Equal Employment Opportunity Commission once hosted a program in which “relevant materials in different languages” were available, according to a public notice numbered 20-020. I couldn’t help observing that (a) this was not what we were looking for, and (b) there were NO decimals in that statement. How much money do the Google guys make, anyway?
Next, I called up my favorite online manservant. I asked Jeeves if .02 was equal to .020, and got a piece of a response that looked hopeful: “0.020 does not equal 0.02 times...”
I clicked on the link to read further, and discovered it had something to do with AA batteries not being acceptable because “L. Amp-hours times hours equal Amp-hours squared, not Amps or Amp-hours.” Apparently it had something to do with radios, and I ended up more confused than ever.
Then I remembered a book called “Math Magic —How to Master Everyday Math Problems.” I bought the book last year, thinking that it would help me prepare for future math homework challenges. I was wrong, but that may have been because I never actually read the book.
I found it, turned to the chapter on decimals, and discovered a paragraph that couldn’t have answered my question more specifically if I’d asked the author myself.
I think there may be something to this book, written by a guy nicknamed, “The Human Calculator.” If the chapters on fractions and decimals aren’t enough to convince me I should read it, the section titled, “Tips, Tax and Change” may do the trick.
I guess I should read it. There’s a 50-50 chance it may do me some good. And that makes something like 100 — doesn’t it?
Copyright 2005, Metropolitan News Company