Pizza Party Invasion

6 teachers like this lesson
Print Lesson


SWBAT show different ways to divide a circle into halves.

Big Idea

Invasion! Aliens have invaded Earth for our pizza. The trouble is they only want pizzas that are divided into halves.

Hook & Objective

10 minutes


Read this fun story (Juan and His Giant Robot: Invasion) to get kids invested in this story! I try to incorporate a wide variety of types of text for kids. Research shows that comics can positively influence literacy amongst struggling readers! The comic I chose can be projected onto your promethean board and requires a Reading A-Z login.


Today we are going to take some alien pizza orders! Your thinking job is: How can I divide a circle into 2 equal parts?

Opening Discussion

7 minutes

I will have chart paper with multiple circles on it. In the center of each circle, make sure to have a center point drawn. Many students will use the center point as a tool in their own work later on.

Present problem: These aliens are very picky! Each of these circles represents one of their pizzas. But all of the aliens want their pizzas with half and half toppings. Our job is to make sure that each share of the pizza is equal.

  • What is a half? What does it mean to be "equal"?

First, I'll share some non-examples. For each circle, we will partner talk about that pizza.

  • Are these parts equal? How do you know?
  • If two aliens shared this pizza, would it be fair? Why not?


After sharing 3-4 non-examples, I'll have students discuss how they could divide this into halves. Most of the research around teaching fractions to young children agrees that students need many experiences folding, cutting, and proving that parts are equal. This early question helps students start to plan and think abstractly. We will confirm or disprove their predictions in a second!

Partner talk: How could I divide this pizza into 2 halves?


Student Work Time and Share

12 minutes

Student Work Time: 7 minutes

Each student needs a circle outline to cut out. Students will do one to share with a partner.

Students choose 2 ingredients that they will put on their pizza. They will half the pizza and put an ingredient on each half. 

Student Share: 5 minutes

Partner talk: Share your pizza with one person. After you share, tell your partner, "I agree that your parts are equal or I disagree".

I will quickly share multiple ways students divided the pizza into halves. 

Summative Question: How are you sure that all of these are equal?

I'll quickly expose students to the idea of the center point. I'll tell students, "Mathematicians use the center point to help make sure they always divide the circle into halves."

Independent Practice

7 minutes

Students quickly show multiple ways to divide the pizzas. Then students will write about one of their pizzas. This is an easy time to connect what they are learning to writing, and is aligned to the CCSS shift of writing across the curriculum. See Example Student Writing for how one student described how she divided her pizza!

The recording sheet for this activity is attached! 

One or two students showed this Misconception. As a result, we all came back together and tested whether or not those pieces were equal. 

You can watch the class discussion here! Are the pieces equal?

Connect to Clocks

10 minutes

Quick Model: We will quickly look at a clock and divide the clock into half on the 30 minute mark. See how I did this on my Dry Erase clock. Then we will practice a few half hour times together. 

Student Independent Review: Students will do some review clocks on their own. I get my clock review from Math Fact Cafe, where you can generate all of your own pdf math worksheets for clocks.