tag:blogger.com,1999:blog-6651514617266100245.post166903425048965455..comments2024-01-03T04:58:04.221-05:00Comments on I Hope This Old Train Breaks Down...: What do we NEED to know?Unknownnoreply@blogger.comBlogger4125tag:blogger.com,1999:blog-6651514617266100245.post-50059909616896448722012-03-25T06:20:45.853-04:002012-03-25T06:20:45.853-04:00I love your blog!! You seem to have some great mat...I love your blog!! You seem to have some great math-teaching ideas, Fawn, that are both fun and conceptually relevant. What a gem for me to follow (and I liked your riblet recipe as well!!). <br /><br />xoxx,<br />Mimiuntilnextstophttps://www.blogger.com/profile/15285583728476473117noreply@blogger.comtag:blogger.com,1999:blog-6651514617266100245.post-2027662928727576172012-03-24T03:27:10.379-04:002012-03-24T03:27:10.379-04:00I don't teach 7th graders, but the 8th graders...I don't teach 7th graders, but the 8th graders I have for algebra still don't quite know the relationship between base and height. Oblique triangles freak them out! Cutting and rearranging is so key, like you're doing, instead of memorizing formulas! I do teach geometry to 8th graders ("advanced" group) and I have the kids draw trapezoids and rhombuses on grid paper and reshape them in whatever ways to figure out the area on their own. Funny, one student even said to me, "So later you'll expect us to figure out the VOLUME formulas on our own also?" Thanks, Mimi!Fawn Nguyenhttp://fawnnguyen.comnoreply@blogger.comtag:blogger.com,1999:blog-6651514617266100245.post-83727363889621638722012-03-22T13:50:08.150-04:002012-03-22T13:50:08.150-04:00Thanks for the suggestion! We did triangles first ...Thanks for the suggestion! We did triangles first and they figured out the 1/2 bh rule themselves by playing with rubber bands on a geoboard (and then later they extended this to sheared triangles, when they decided after cutting and shearing and pasting back down a sheared triangle, that its area remains constant). But, I am intrigued by the triangle-parallelogram connection. I've never seen that transformation before (but I checked it out on Wolfram Alpha to see what you mean), so thanks for the tip!!!untilnextstophttps://www.blogger.com/profile/15285583728476473117noreply@blogger.comtag:blogger.com,1999:blog-6651514617266100245.post-16326747645369183472012-03-22T12:43:35.578-04:002012-03-22T12:43:35.578-04:00When doing triangle areas, you can use "cut-a...When doing triangle areas, you can use "cut-and-rearrange" to turn the triangle into a parallelogram. Doing this after turning the parallelogram into a rectangle can help kids see where the A = 1/2 bh formula comes from. You can basically do this with any polygon, but it's a nice progression.Anonymousnoreply@blogger.com