Little Problems with Big Solutions

My 7th graders did something today that I just hSolve it page for Polygonsave to blog about. It’s the first time we used the large white boards AND presented in groups, and it was GREAT! We used the “solve it” problem from Mathematics Teaching in the Middle School. I had the kids be in groups of 4 as much as possible and each group of 2 had to draw the 3 shapes: a triangle, rectangle and trapezoid that had the same areas – but the pairs at the same table had to have different areas for their shapes. The shapes had to be drawn to scale, so each pair had a ruler and marker, and they shared the white board and eraser. When they were finished drawing they had to find the perimeters of the shapes, and see which was smallest and largest. The directions wanted the pairs to compare and see if both had the same shape as smallest and largest (and middle!) perimeter, but we really didn’t get to formally do that, because, I had each group get up and present to the class! The boards were interesting to look at because half was upside down, but they turned them around based on who was presenting.

What was so AWESOME about this was they had to 1) figure out what area tPolygons on white boards 1hey wanted to use, and the table couldn’t be doing the same thing! 2) they had to know the formulas for the shapes, and NONE of the groups messed up the area of a triangle! I know if it had been a test, there would have been several kids that didn’t remember the 1/2. 3) They had to THINK about what to do for the triangle (especially if they didn’t make a right triangle) and the trapezoid! There were a couple of teams that had base1 as 1.25 inches and base2 as .75 inches to make the area work out, which was awesome (I haven’t said that word enough). When would they willingly pick decimals in their regular work? 4) They all had to get up in front of the class and talk!

A couple of groups didn’t draw their shapes to scale, so we got to talk about that (attend to precision!), and a few others had their height the same as the slant height on their isosceles trapezoids (we discussed how the slant height CANNOT be the same as a vertical height), but overall I was BLOWN AWAY. They presented, they created, they thought! And they never complained! That’s why I had to blog about it (I’ve been so bad, I will really try and do more.)

Tomorrow I’m giving back their tests from Wednesday. It won’t be as pretty. If they could just solve their equations with integer operations on white boards – I’m sure the errors would be minimal! One more picture:Polygons on white boards 2

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About debboden

I teach middle school math in Thousand Oaks, California. I love my job! When I'm not teaching, or thinking about teaching, I love to ride horses, read, take Zumba classes and be with my family and friends.
This entry was posted in Area & Perimeter, Large White Boards and tagged , , . Bookmark the permalink.

One Response to Little Problems with Big Solutions

  1. Sarah Harlan says:

    Wow! No wonder you were blown away – such an excellent teacher you are! I am now blown away BY YOU!! Keep up the good work, as you always do (and keep sending me your blogs). Love, Mom

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