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Posted By: Nautigal Triangle question - 2nd grade - 12/03/13 04:33 AM
This has to be ridiculously simple, and I'm just overthinking it. DD7 has an Everyday Math page that asks her to draw a triangle that is 4cm on all sides.

I can do it with a compass, no problem. I showed her that. But that can't be what they are expecting her to do. Is there something obvious that I'm overlooking? She had no idea how to do it, and said they hadn't learned that, which may or may not be true -- she gets really silly about math things and doesn't pay a lot of attention sometimes.
Posted By: mama2three Re: Triangle question - 2nd grade - 12/03/13 04:52 AM
FWIW, I have a 2nd grader and I'd guess that they want her to "rough" out an equi triangle with sides measuring close to 4 cm and labeled as such. Just a simple eyeballed one.
Posted By: 22B Re: Triangle question - 2nd grade - 12/03/13 05:50 AM
Is this one of those problems that you have to do in five different ways?
Posted By: Nautigal Re: Triangle question - 2nd grade - 12/03/13 06:01 AM
Gawd, I hope not! I can only think of the one way. Although, as mama says, it could be just a simple eyeball thing, so that's two.

Posted By: polarbear Re: Triangle question - 2nd grade - 12/03/13 07:54 AM
You can do it without a protractor, and I think it's likely they are just having the kids figure out a way to do it, either by eyeballing it or by doing something like marking the correct amount of cms on three pieces of scrap paper and holding together to make the outline of the triangle etc.

polarbear
Posted By: Lovemydd Re: Triangle question - 2nd grade - 12/03/13 12:03 PM
How about drawing a straight line 4cm long. Draw a line perpendicular (eyeball) to this line from the midpoint(2cm). Make this line really faint. Then keep the ruler at one end point on the horizontal line and keep moving it till it meets the vertical line and measures 4 cm. then complete the triangle. Wouldn't that work? Oh boy, I better brush up on my elementary math.
Posted By: NotSoGifted Re: Triangle question - 2nd grade - 12/03/13 01:33 PM
Not an easy problem. I wonder how my perfectionist kid, DD16, made it through Everyday Math. She did so without complaining, and even now she doesn't think it was a bad experience. DD9 is in her first year of public school and hates Everyday Math. Complains they don't spend enough time on any one topic and they throw random stuff in that they haven't learned yet (such as primes). Previously she was in a school that used a European math text (French). While the French do "spiral" in math, they spend more time on each topic and the explanations are much better than I have seen in American texts.

To do that problem properly, you need to know some geometry. I'd call it an 8th grade problem.
Posted By: ColinsMum Re: Triangle question - 2nd grade - 12/03/13 01:54 PM
It's interesting, though, that this thread has already come up with 5, count'em, five, significantly different ways to do the question (ruler and compass construction; purely by eye; use a protractor and measure; use the perpendicular bisector of a side to help guide the eye; manipulate edges). Between them these bring out a lot of important geometry, especially that you can use "equal angles" or "equal sides" in this case (in more advanced geometry, a lot of the art is knowing when to go after angle, when sides, and when you can play them off). At the risk of making everyone hate me, I think this suggests it's quite a good question! ETA with a high ceiling (fully understanding all the methods and their pros and cons) and low floor (gaining a basic understanding of what an equilateral triangle is), as the educationalists say - the only pitfall really is kids being too scared to have a go. ETAagain infinitely better as guided exploration in class than as homework, though!
Posted By: Zen Scanner Re: Triangle question - 2nd grade - 12/03/13 02:48 PM
Originally Posted by ColinsMum
At the risk of making everyone hate me, I think this suggests it's quite a good question! ETA with a high ceiling (fully understanding all the methods and their pros and cons) and low floor (gaining a basic understanding of what an equilateral triangle is), as the educationalists say - the only pitfall really is kids being too scared to have a go. ETAagain infinitely better as guided exploration in class than as homework, though!

I agree, and the biggest pitfall for poorly implemented exploration type math seems to be when the teacher expects each student to list exactly 4 specific methods of achieving the result. Undermines the whole thing.

I wonder if they circle back on the question in the next class and list the different approaches and the thoughts behind those approaches.
Posted By: jack'smom Re: Triangle question - 2nd grade - 12/03/13 03:51 PM
I don't know if the CC math will be any better, but our school currently uses Everyday Math, and I figure it couldn't be any worse!
In third grade, they drew rays and they had to name them. (I thought, name it like AB or something, from the points on the ray).
My son labeled one "David" and another "Tony." He said those were his best friends' names!
I thought he was goofing around but that was what the Everyday Math publishers wanted- a way for children to "get comfortable" with math!!
Posted By: rachsr Re: Triangle question - 2nd grade - 12/03/13 04:16 PM
I remember this one since it made me think exactly what you wrote. I was wondering if they had been taught how to use the protractor or the compass but decided to keep mum and let DS tackle it by himself - he just used a scale and drew a triangle of approximately equal length sides. HE didn't throw a fit about the three sides being perfectly equal because he had a friend waiting outside waiting to play.
Posted By: Nautigal Re: Triangle question - 2nd grade - 12/03/13 04:45 PM
Originally Posted by jack'smom
In third grade, they drew rays and they had to name them. (I thought, name it like AB or something, from the points on the ray).
My son labeled one "David" and another "Tony." He said those were his best friends' names!
I thought he was goofing around but that was what the Everyday Math publishers wanted- a way for children to "get comfortable" with math!!

That is too funny! laugh I would definitely have tried to shut down that approach, with exactly the thought that you were having! I can see that discussion with DD now. "No, honey, you can't name them Gavin and Ty." "But teacher said so!"

Well, about the triangle -- I'm glad it's not just me. I thought I was missing something really stupid, there. I'll have to ask the teacher exactly what it was they were looking for.

It was made more complicated by the fact that I couldn't find a compass and had to make one from a pair of scissors. I thought about cutting out a circle the right size, instead, but I didn't want to make it seem that much more difficult for DD.
Posted By: mecreature Re: Triangle question - 2nd grade - 12/03/13 06:17 PM
I see nothing wrong with the question. I know sometimes my ds got a full explanation at school that some how never made it home.

Anything that initiates dialog at home cannot be a bad thing.

I to hope the discussion continued at school the next day. I bet it did.
Posted By: Nautigal Re: Triangle question - 2nd grade - 12/04/13 06:38 PM
I got an answer from the teacher. As it turns out, they were supposed to draw a 4cm line segment and then eyeball it to draw two more 4cm segments from those points. Which is what we started out with, but it was tricky to get them to come out in the right spots. She said they are just introducing them to the concepts.

Because, you know, math and geometry aren't precise things. Just guess at it.

Hmph. I think we'll name it Tony when it's finished.
Posted By: 22B Re: Triangle question - 2nd grade - 12/04/13 07:14 PM
Originally Posted by Nautigal
As it turns out, they were supposed to ...

Aha! So there was a specific intended method.
Posted By: ultramarina Re: Triangle question - 2nd grade - 12/04/13 07:42 PM
Quote
Hmph. I think we'll name it Tony when it's finished.
Bwah!
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