Can't do math?

Post 22 of 30 #MTBoS30

This happened at a training we did a few weeks ago. We were modeling how to do a certain kind of student driven helping process that comes from AVID. One teacher was to be the "guinea pig."  It was a math problem, so the history teacher volunteered because she "can't really do math."

It was one of those logic problems you might have seen.  A boat is sitting at anchor.  There is a rope ladder hanging over the side of the boat into the water. Five feet of the ladder are out of the water. The tide is rising at the rate of 8" per hour. How much of the ladder will be showing after 6 hours?  Don't read any farther if you want to work it out for yourself.

It's okay, I'll wait.

...

No problem.

...

Figured it out yet?

Yeah, maybe you've figured out that it is a trick question by now, but the history teacher immediately started multiplying 6 by 8. (I, of course, was thinking of Robert Kaplinsky's shepherd problem as she was doing this, but this is not as bad because if you don't really think about the situation, you are going to fall for the trick.) What I found fascinating, though, was the way she multiplied 6 and 8.

She said, "I can't remember 6 times 8, but I know 6 times 6 is 36, so I'll add 12 because that's 6 times 2 and I'll get 6 times 8."

She was actually reasoning it out loud for us.

Then she piped up with "That's how bad I am at math!"

The special ed teacher and I immediately tried to set her straight by explaining that that's exactly how we are trying to teach math in the common core and that she had just demonstrated wonderful flexibility with numbers and constructed her answer based on logic rather than having a memorized answer with no understanding.

She did figure out the trick, though. Our job was to ask her questions that would help her find the solution without just telling her how to do the problem. She had drawn a picture of the boat, so I asked her to add the water to her picture. Finally, I asked her to draw where the new waterline would be on the boat after 6 hours. She started making marks very seriously intending to find this "new" water level. That's when she finally got it--the boat floats!  

We didn't succeed, by the way.  She still thinks she's bad at math.