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Next Year’s Number Line

Like most math classrooms, I’ve got a number line. My kids use the hell out of it after we learn about negative numbers, some up to the end of the school year. We’ve got a week and a half left, and the kids are restless. I didn’t like the number line I bought this year, […]

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Questions 1

My students sit at tables instead of individual desks. To reduce the incidence of cheating, I create two versions for each test. I’ve learned in the process that similar looking problems actually can vary quite a bit in their effectiveness. Here’s my first example: -4 – 9 = -9 – 4 = Similar problems, same […]

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Little People

The last time I effectively taught adding & subtracting with negative numbers I was on to a good idea, but there were a couple of faults – only the kids actually walking the number line were engaged, and they lost their positional cues as soon as they went back to their desk. So this time, […]

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Forwards and Backwards redux

So that lesson on multiplying negative and positive numbers still worked great for my algebra kids, understanding wise, even if they looked a little nonplussed at the end of it1. As a recap, it goes through various combinations of video of a student walking forwards, or backwards, and then running the video forwards and backwards. […]

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Add/Subtract Reteach

I had one class of students who never got a grasp on how addition and subtraction works with negative numbers. I can’t blame them much – that was what I was covering during the period that one of their classmates got shot. I obviously didn’t accommodate that as well as I could or should have. […]

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Forwards & Backwards

I’ve done a lot of opinionating, and not so much lesson sharing. I’ve wanted to, but the adding and subtracting of negatives didn’t go well, and I had to reteach them focusing on the mechanics, slowly tying those mechanics to the manipulative practice before. It went well, but was just old fashioned grunt work teaching, […]

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I stole another idea from my math coach1. After the quiz today, I gave the kids a bit of relief, and used the built in camera on my new laptop to set up a recording area, and had those kids who wanted to show off walk forwards & backwards (with big arrow signs pointing in […]

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Today I gave a quiz on adding & subtracting negative numbers. It went quite horribly – I obviously dropped the ball again somewhere. The only time I ever had kids get it easily and quickly was when I likened positive numbers to people, and negative numbers to raptors1. The raptors eat a person, take a […]

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Negatives: “More”?

It took a while to dawn on me: I’d obviously missed something. I got frustrated when the kids couldn’t cancel pairs. All they had to do was match up a red with a yellow, move them to the side, and count what was left over. They could add more pairs, and the number could stay […]

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Negative Numbers: Adding/Subtracting Followup

About 1/3 of my kids got got through the subtraction. About 1/3 thought they remembered the rules from 7th grade, and bypassed the algebra tiles, and got most of the questions wrong.[1] The final third did pretty well on addition, and then got confused on how to do the subtraction. I can’t get frustrated, because […]

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