Sunday, 26 February 2012

Math: Geometry Problem Solving

We continue to have a great time in math this term.  The kids have been exploring 3D objects through sorting them into groups according to one attribute (e.g. these all have 4 sides), building towers and looking for these shapes in the real world.  When we work with 2D shapes, we also sort them according to one attribute and also replicate objects and create other shapes using shape materials such as pattern blocks and tangrams.  We still do problem solving on a regular basis.  Here is a geometry related problem that we completed recently.

There are 3 shapes in a bag.  The total number of sides is 13.  What could the shapes be?

What I like about this problem is that it allows the children to demonstrate their knowledge of 2 dimensional shapes and there are many possible outcomes.

The kids organize their thinking in many different ways.  It is another thing I love about problem solving.  We almost always include a debrief or sharing time at then end of a problem solving lesson.  We ask kids to share their strategies.  Sometimes we let anyone share.  Other times, we target specific kids to share a strategy that we think could support other students.  Throughout the year, students develop quite a repertoire of strategies that they are comfortable using.

Some used equations with the shape name written underneath.

Other children created equations, but instead of numbers drew the shapes.

Others chose to "act it out" with pattern blocks and then trace the blocks onto the page.

Some kids asked me the name of ten sided and thirteen sides shape so they could use them in their equations.  Thanks to google we had some fun trying to pronounce some of their names.

This student, used equations and then the initial letter of each shape underneath to show which shape he was referring to.

1 comment:

1. What a great way to tie geometry to problem solving. Where do you two come up with these great ideas? Thank you for sharing all your wisdom! I can't wait to try this lesson out.

Recently we've been doing geometry in my class and what I noticed through my most recent assessment, is that my students are having a hard time understanding that we use different language when discussing polygons versus 3-D shapes. They have begun to refer to the sides of triangles, squares, etc... as edges and corners as vertices. I think I will use this lesson to really instil the differences.