Co-Teaching Lesson: Perimeter (Sue/Anastasia)

This is the 3-part lesson we observed during our co-teaching session with Sue and Anastasia at Bendale Junior this morning.

Materials from our co-teaching session can be found through these links:
Three-part lesson plan
KWC Chart
Assessment for Learning template

Prior to the lesson:
Students in Anastasia's class had been learning about length and perimeter prior to this lesson.  This lesson is more of a culminating task.

Part 1: Activation of Prior Knowledge
Sue asked students: What is perimeter?  After students did a think-pair-share with the person beside them, Sue gathered a definition and recorded it on chart paper.  Students could refer to this while solving the problem.

Sue then showed the class a picture of a triangle with some measurements.  She asked students to figure out the perimeter of the shape.  After a think-pair-share, Sue recorded some student thinking on the chart paper.

Part 2: Working on It
Anastasia gave each pair a copy on the problem.  The problem was taken from the Grade 3 EQAO booklet (Spring 2009, #100.

After read the problem over, she completed the KWC chart with the class.

Anastasia also clarified what the word 'justify' meant so that students knew exactly what she was looking for in terms of their communication.

She also reminded students about the different measurement tools they could use to help them solve the problem.

After students started to work on the problem, Sue and Anastasia walked around to look for specific student thinking to highlight during the Part 3 of the lesson.

Part 3: Reflecting and Connecting

 During the part 2 of the lesson, we noticed that students were getting different measurements of each of the rectangle and different perimeters.  There were several pairs who also decided that the perimeters were the same.  As a result of this, pairs were chosen to highlight these observations during the math congress

This pair assumed that the second rectangle was a square and decided that both rectangles had the same perimeter.

This pair got the right answer but had difficulty using the appropriate language (most popular, least popular).

This was one of two pairs who noticed that the side lengths were not exact measurements.  So they decided to use 'about 8cm and 2 and a half cm".  During their sharing, they mentioned that they forgot to add the halves but it wouldn't have made a difference to their answer.



This pair did not share but used a great strategy of just measuring the long sides.  We're not sure where they went wrong in their calculations.

Explicit Teaching

There were a couple of key points that Anastasia and Sue brought out to end off the lesson:

- the only way you can know for sure that's a square is to measure it

- when you measure a length that isn't an exact number, you can round up or down

Next Steps

As a group, we talked about several key points in the student work:

- we need to give students more unfriendly measurements

- Anastasia needs to discuss rounding up and down with her class  (some kids rounded up for one measurement and down for another so they ended up with wrong perimeter)

We now look forward to our next demonstration lesson at our next PLC!