# Finding Rectangles

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## Objective

SWBAT compose and decompose polygons to make rectangles.

#### Big Idea

Students will look for as many rectangles as they can from a given set of shapes. The students will find as many solutions as they can.

## Warm Up

10 minutes

I start with a warmup that I have done in every lesson for this unit.  I want to encourage students to talk about defining attributes of different shapes.

You will be using Shape Cards for this activity.  I have included a sample copy from the Investigations Program. The cards have a copyright so I could not include all of the shapes from the set.  You will have to make up your own.

I have the students sit on the carpet and face the Smart Board.  They will each need a pencil, blank sheet and a clipboard.

"I am going to show you a shape.  I will flash it for a few seconds.  I want you to look t the shape and then draw it.  I want you to think of the features of the shape as you draw it. I will flash the shape twice (15 seconds between each time).  This way you will be able to check your work.  When you are done, I will display the image again and ask you to tell me what you noticed about the shape and who it helped you draw it."

There is a video (Warm Up) that models a student explaining what she noticed with a triangle.  I will repeat this process with a square, circle, and a half circle.

In this activity, I want students to focus not he defining attributes of a shape (triangle has three sides, closed).  Later on in the lesson the students will focus on non-defining attributes (color, width, size).  This allows students to meet CCSS.MATH.CONTENT.1.G.A.1.

## Introduction to Finding Shapes

15 minutes

Before starting this part of the lesson, it'd be great for you to watch Finding Triangles.  This way you will have an understanding of what I am introducing to the students.

"I would like you to look at the triangles on the whiteboard.  How many triangles do you see?"

Most likely the students will identify the four individual triangles (not the overlapping ones).

"I will outline each one that you identify in a different color.  Are there any others?"

I will then call up kids to color in another one that they saw.

"Today, you will be doing the same thing but with rectangles."

Note: You may need to reinforce the defining attributes of a triangle.  Meaning, make sure that students understand the the defining attributes of a shape will not change (i.e. triangles have three sides) but non defining (colors, size, thickness) can change.

This activity has the students composing two-dimensional shapes to create a composite shape, and compose new shapes from the composite shape (CCSS.MATH.CONTENT.1.G.A.2).

## Finding Rectangles

40 minutes

Note:  This activity cam from the illustrative mathematics website.  It is an open source sight that models examples of each standard and give an activity that incorporates that standard.

Advanced Preparation:  You will need to make enough copies for each student or team of two to have 11 copies of Blank Rectangle Sheet.

"I am going to ask you to work in teams of two or on your own with this activity.  It will be up to you.  Your job is to find as many different rectangles as possible.  You will notice that each sheet has a space for a number.  You will use a blank sheet for each rectangle that you find and number that answer (1 for the fist one, 2 for the 2nd one, etc.).  You can use markers to color in each rectangle.  I will tell you that there is more than 5 but less than 12 different rectangles.  I want to see how many you can find."

I have included a video, Student Finding Rectangles, that captures a student explaining as he works on this activity.

## Continued Practice

5 minutes

I will ask the students to meet me on the carpet and hand out their sheet for today's Mad Minute exercise.  This routine was introduced in a previous lesson.  Please check out the link to get a full overview of this routine.

I want to really focus on fact fluency and build upon the students ability to solve within ten fluently (CCSS.MATH.CONTENT.1.OA.C.6).  I am going to use the Mad Minute Routine.  This is a very "old school" routine, but I truly feel students need practice in performing task for fluency in a timed fashion.  Students need to obtain fact fluency in order to have success with multiplicative reasoning.  Students who don't gain this addition fact fluency by the end of 2nd grade tend to struggle with the multiplicative reasoning in third.  Having this fluency also allows them to work on more complex tasks because the have the fact recall to focus on the higher level concepts.