Picnic Basket Fractions

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Objective

SWBAT divide squares and rectangles into halves. SWBAT define half.

Big Idea

Take students to a pretend picnic and give them hands-on practice dividing shapes into halves!

Objective

5 minutes

This lesson is a great time to connect to past learning about the term "equal". Students in first grade encounter this word throughout the year, consistently practicing the idea that equal means the same amount. In this lesson, students determine how to divide shapes so that 2 people could each have fair shares. It is worth noting that many times I use the word fair in my day to day classroom interactions to not necessarily mean equal. To be sure that students enter the lesson with a clear understanding of the language, I would start by explaining that fair and equal in math refer to something more precise. In this case, fair means both people sharing get the exact same amount. This also helps students practice communicating precisely (MP6). 

Review past learning:

When we talked about the word “equal”, we talked about how equal means the same, or fair. Sometimes when we use the word fair, it’s when we had to share something. Today we are going to be sharing a shape with one other person.

Connect: Why does this matter?

In 2nd grade, 3rd grade and even in high school, you will be working with something called fractions. The work we do today will help you learn some important things about fractions that will help you when you get older.

Objective:

Today your thinking job is: How can I make a half and share these objects fairly with one other person? 

Opening Discussion

15 minutes

Today we are going to be sharing some things with a partner when we pretend to go on a picnic!

Definition: We are discussing something called fractions today-fraction is just a math word for an equal part of a whole. The fraction we will be focusing on is a half. A half is when you cut something into 2 equal parts-it is two halves.

Present Square: We are going to pretend this square is a brownie.

Now I am going on a picnic with my friend. We both want some brownie. I have to share this brownie so it is fair to my friend, I have to make the two pieces equal. I need to give them half of the brownie.

  • Why do the pieces have to be equal?
  • Watch how I fold this paper to make the brownie equal. If you think it is fair, I want you to show a thumbs up; If you think it isn’t equal, show a thumbs down.
  • Is this equal? Why or why not? 

I’ll fold the paper in different ways. Each time, the students say if it is equal or not. I’ll do 3-4 not equal ways before finally doing a simple fold down the middle that shows 2 equal parts.

Restate: After I finally do the equal shares, I’ll say: “If I gave my partner 1 part of the brownie, then I would give my partner half. Half is this side-we both get the same amount, so we both get half.”

 

Define: When we make halves, 2 people are sharing it equally. 

  • Let me draw my brownie. (T draws square on chart paper). How could I show the way I divided this brownie into 2 equal parts?
  • Now that I showed my brownie, I am going to shade, or color in, the part that I am eating. What do I need to color? What math word do we use to describe this? (half)

Student Share

15 minutes

Present Rectangle: This rectangle is going to be our placemat on our picnic. For vocabulary development, I’ll explain what a placemat is.

Everyone is going to get this rectangle in a second. We have to split this placemat so both people get the same amount of space. You and your partner need to each get half of the placemat. When we make halves, 2 people are sharing it.

Student Work Time:

  • Partner groups each get a “placemat” (construction paper) to work with and start trying to figure out how to make it into halves. 

Student Debrief:

  • Partner Talk: Do you agree that these are halves? Watch this Partner Discussion to hear how a student explained why she agreed. This is aligned to MP3, Construct viable arguments and critique the reasoning of others. This student knew that she agreed with her partner, and articulate why she agreed.

I’ll shows a few placemats that I folded. One that is 3 parts, one that is 4 parts, one that is 2 unequal parts, and one that is 2 equal parts.

  • Partner talk: Which of these placemats is divided into halves?  How are you sure?

Independent Practice

15 minutes

Group A:Intervention

Students cut out and fold only the rectangle pieces. Students show how they folded them on the recording sheet.

Group B: Right on Track

Students cut out and fold all of the pieces to share with a friend on a picnic. Students show how they folded them, and shade in half.

Students do writing piece at the bottom of the recording sheet, which is aligned to the CCSS shift to writing across the curriculum.

Group C: Extension

Because this is the first day, most students will be in Group B. However, for students who are early finishers, push them to think of a different way they could fold each shape. 

Picnic Lunch Recording Sheet and Pieces are attached!

Closing

5 minutes

We will create a "Half" anchor chart. This anchor chart will show multiple shapes that students divided into halves.

We will use this throughout the week as a reference!