6_8_07

Halves discussion:

I asked everyone to take out a hexagon and put it in front of them. Then I said to find a block that was half a hexagon and cover the hexagon with it (ie. find two of them, but I didn't say that). Most kids chose the trapezoid but couldn't verbalize how they knew it was half. (Not surprising, it's very hard). We finally got to the fact that for halves there is a magic number and a magic word: the number is 2 and the word is equal. (Luckily they are very familiar with the word equal!). So then I had them take out a rhombus and then find a block that was half a rhombus and cover the rhombus with it. They got that one, and then we double-checked it -- were there two of them? Were they equal? After that they got out trapezoids and I had them put a rhombus and a triangle on top and asked if either of those blocks were a half. Some thought yes, some thought no, and then we checked -- were there two? Were they equal? And figured out that they weren't halves.

Last I had them cover the trapezoid with 3 triangles. I asked if the triangles were halves, and we checked the "magic word" and the "magic number" and figured out they weren't. I asked if anyone knew what they were called. No one could come up with it, but when I wrote "thirds" on the board some knew it. We started a chart that said the magic word and the magic number for each fraction. I thought it would be fun to continue it next week but I'll have to use things other than just pattern blocks (which is a good idea anyway). I thought of trying out cuisinnaire rods to review halves and thirds and then do fourths, etc.