That’s a Negative

I have never taught a class who had such a hard time with negative numbers.  I told them it was just a matter of subtracting more than you actually had.  I showed them how to count backward on the number line.  I talked to them about borrowing money.  They didn’t get it.

In frustration I finally wailed, “Come on people, it is subtraction!  You learned this in first grade!”

Rick muttered, “Yeah, but that was a long time ago.”

I had Cindi and Cyndi come to the front of the room.  We did a little borrowing lunch money role play thing for the class.  Light began to dawn.   Then I made a mistake.  I told them about buying my car.  I said that the bank paid for it and let me have it, but I have to make monthly payments.  Rico says, “Well if they bought it and then gave it to you, just don’t make the payments.”

I said, “Then they would come and get the car.”

Rico said, “But that’s stealing.”

I said, “No, Rico.  The bank owns the car.  If I don’t make the payments I am the one stealing, and they come and get their property back.”

Rico said, “Oh, I get it.  You’re only renting then.”

I picked up the pointer and turned back to the number line.  “Okay,” I said, “Let’s try counting backward again.”

11 thoughts on “That’s a Negative

  1. Wait, Professor O’Ceallaigh, no teaching tips?

    And twins Cindy and Cyndi aren’t — except in silly, and that’s pretty much part of every ten year old girl.

    As to tomorrow — that’s the unit test, so we worked on it today until they finally got it. Of course, that meant we short changed Science for time, but that Science is expendable, right? :*

  2. I feel for your kids. I just don’t grok math. I’ve never been diagnosed, but I strongly suspect I am dyscalculic. I know that negative numbers were difficult, but I finally got them. However I still believe that my teachers were lying to me about the whole imaginary numbers thing. Math is still a real sore spot for me. Good luck to them.

  3. Brig — one of the reasons I am a good math teacher (IMHO) is because I didn’t get math. I am patient, and calm and can usually understand by a child’s questions just what it is they didn’t get, so I can help them with it. The problem comes when the whole class doesn’t get it, and no one is asking intelligent questions. You’ve got to know that, I don’t get it! isn’t helpful to the teacher.

  4. It’s so good you give lots of real life examples. I had so many teachers that tried to teach math in purely conceptual models. I often run across adults who had the same kind of teachers and I re-teach math concepts to them now and their response is “Oh, is that all it is? Now I get it.” So much better to do it right the first time.

  5. LOL! Seems to me that YOU are the one havin’ a hard time here…. Rico got the car thing right on the money! You are “renting to buy”… I remember having a hard time with negatives too… of course, it IS math … but one day it just clicked – and I GOT it! (unlike algebra…) I KNOW you’re 5th graders are smarter than me – so they’ll get it too!

  6. Nessa — yeah, my teachers never gave real life scenarios, either. But learning has to be personal or you don’t connect. Everything in my classroom comes with real life connections.

    Melli — yes, Rico got the car thing all too well. He’s not one of my best math students, but his perspectives on life are clear, well thought out and logical.

  7. this reminds me of an old policemen joke (are these politically correct?)
    where the teacher also explains negative numbers and he says something like that: imagine there’s 10 people on the bus. 12 people exit on the next station. now 2 people have to enter in order for the bus to be empty.

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