SWBAT partition circles and rectangles into two equal shares.

Let’s Share! In this lesson students will learn to divide circles and rectangles into halves.

10 minutes

I start this lesson by reading aloud, “Give Me Half” (the YouTube version can be found here: Give Me Half). I like to begin this lesson with this read aloud because it not only introduces the concept of halves and wholes, but it is based around the concept of sharing a pizza. Sharing is something that all students can relate to and can easily understand.

After reading the story, I demonstrate how to fold a shape to show one whole and two halves using the student cut outs. I then have them cut out the shapes from the Halves_student cutouts.docx and have them practice folding the shapes in half.

For children to understand halves (1.G.A.3), they must understand that a shape in itself is a *whole*. When a *whole* has two equal parts, these equal parts are called *halves*. Folding a two-dimensional shape helps children see one whole and two halves. Without measuring and counting, children can tell if the parts made by folding are fair shares or not. I like to encourage children to use words such as *fair shares*, *one whole* or *one*, and the name halves. Using the language of fractions with geometric models helps children establish their understanding of fractional parts (MP6).

15 minutes

I then draw two large rectangles on the board. I call on two children to divide one rectangle into two equal parts and the other rectangle into two unequal parts. Discuss each pair of drawings.

**Which drawing shows equal parts? How do you know?****How do you know that the other drawing shows unequal parts?**

I then display the first slide of the Halves.ppt and read the following problem aloud:

*Two friends share the sandwich on the left. How can they cut the sandwich so each gets an equal share?*

**How many equal shares do you need?**(2)

I have a volunteer draw a line to divide the sandwich into two equal shares.

**Now look at the whole sandwich. How can you describe its shares?**(The whole sandwich is made up of two equal shares.)

I continue by reading the following problem:

*Two other friends share the sandwich on the right. How could this sandwich be cut a different way so each friend gets an equal share?*

If children drew a vertical line in the first sandwich, I would encourage them to draw a horizontal line or a diagonal line to show equal shares in the second sandwich.

**When you cut a shape into equal shares, is each share bigger or smaller than the whole. Explain.**(Each share is smaller than the whole because you are cutting it up to share.)

Next I display the second slide of the Halves.ppt and work through the model with children.

**How many equal shares are shown?**2**How many halves are shown?**2**How many halves make 1 whole?**2

I emphasize that when a shape has two equal shares, the equal shares are called *halves*, and each individual share is called a *half *(MP6).

30 minutes

I then display the third slide of the PPT, which also corresponds with the first few problems of the Halves_worksheet.docx. I have children notice that the same shape is shown in questions 1 and 2, and the same shape is shown in questions 3 and 4. I encourage children to show halves for the same shape in a different way. Once children complete questions 1–4, I ask the following question.

**Is there more than one way to show halves on a shape? Explain.**(Yes. As long as the two parts are equal, the line can go in different places.)

Next, once students have understood the concept of equal shares, I release them to complete the worksheet independently.

In this picture, you can see a student who has successfully mastered the concept of what is half of a circle or rectangle:

5 minutes

To close out the lesson, I have students draw a circle and separate it into halves and color each half a different color.