Students will be able to create the dimensions of appropriately sized kennels for different sizes and types of dogs, given the total area to be used.

Students will be able to use strategies to solve real-world problems involving area and perimeter.

5 minutes

In order to motivate and excite my students, I began today with a photo of my dog Riley on the projector. They hear stories about my dog almost daily and I use that personal connection and high interest topic (pets!) with my third graders often.

Today I share a personal story of trying to find a boarding kennel for Riley because I'll be away for the holiday season. I tell students that I was having a difficult time finding a kennel, and was wondering what I would do.

After explaining to them that I finally solved the problem by asking a friend to take her, I explained that I thought our community needed more dog boarding businesses. I asked them, could they help and explained they would be the architects of a new kennel. This was a good move, as many cheered! Connecting with something personal is always motivating.

10 minutes

As the students gather at the community area for the mini-lesson, I display a large dot paper with a rectangle already drawn. I also have copies of it for the partnerships. (There are many free dot paper resources on the internet.)

I explain that this rectangle represents the warehouse floor that was purchased to build the boarding kennel in. *What do you think you'll need to know before you can begin working on a design plan for the dog’s kennels? *

Ask the students to turn and talk to their neighbor about their ideas. You will be listening for someone to state that they need to know the total area of the floor. They probably will phrase that differently, recognizing that the drawing only shows a shape and saying they need to know how much space that is. This will be your lead in to the activity.

*Students, I heard someone say that we might need to know what the total area of the warehouse is before we begin to plan. Does anyone agree? Why? What do we know about finding the area of a very large space? Please turn and talk about how you might attempt to find the area of this space.*

The rectangle I used was 21cm by 26cm. The students had ideas of making 10 by 10 rectangles, 20 by 20, even 5 by 5’s.

20 minutes

Once you feel they have created a bit of a plan with their partner, send them off with a copy of the warehouse floor and let them at it. I did not tell the how to find the area at all and each group did something different, but all of them created smaller areas to add together, so I know our past lessons have taken hold!

As students work, watch to see if they are decomposing into values easy to work with, like base 5 or base 10. If they aren’t, this is your teaching point. If I found students that were working in these bases, I asked them to explain to me why they chose to do it that way. I also sent students to visit with other groups that had interesting strategies to compare and describe what they were doing. There is no reason to wait until the close of a lesson to have students share their thinking. Many times I find it is more powerful for students to share their work and thinking as it happens rather than waiting until we close. Thoughts and understandings grow when they are discussed and critiqued in real time (MP3)

This partnership decided to create several smaller areas to find the total.

15 minutes

As a closing, I review with the students that we will be planning a boarding kennel for many dogs within this large space, so we will continue to work on our project. It is important that each dog have its own private space.

Then I ask students to share how they determined the total area of the warehouse. We work, as a class, on any mistakes we find and come to agreement that we have 546 square feet to work with tomorrow.