# “How am I supposed to know?”

Posted on November 30, 2010

It’s multiple choice:   3 mm, cm, or m.   It’s a paper clip. “But couldn’t you measure it in cm or mm?”

Okay, we’ve opened the *thinking* door 🙂    At first, we were looking for What Math Procedure To Do.   “Look at the number.  Imagine.  How long would 3 mm be?”   Oh!   …  Learning to *think* about math takes some serious unlearning…

This mornings Small Success Story was with that new thing about graphing.   YEs, we have the skill of plotting the points to “need practice but I have the skill” stage.   Oops, the next problem is to plot y=2x-4.    Okay, we’ll plot (2,4) — but then what?

Wrestle with “it’s like a formula.”  We’ve done formulas with some success, a few weeks ago… formulae for perimeter and area and the like and when we could see circles and squares and figure out what volume and area were and practice that, too, success happened.    However, there’s no circle here.

HOweverever, when I dramatically conveyed with words and gestures (but no concrete materials!) the idea that I took my number — money, perhaps? — and doubled it… but then took two away… what would I have?   So!   Semiconcrete was good enough, with some exploration.   I even briefly broached “and if you make y zero,”… with the idea that you have to find *what* number you could double… that was *just* big enough, so if you took the four away you broke even and were back at zero.

It’s still at teh “okay, it kinda makes sense when *you* talk about it,” which is not “I can teach it,” but we’ll get closer to that (and we’re not training to be a teacher).

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