How Many Squares?
Students will learn out how to partition a rectangle using by partitioning shapes with rows and columns.
- Display a large rectangle on the projector using a piece of paper or pre-cut rectangle.
- Say, “This is my birthday cake. I want to see how many pieces of cake I have to share. Each piece needs to be this big (hold up a square color tile). How can I figure out how many pieces of cake there are?”
- Have students turn and talk to a partner to share their ideas. Then invite a few pairs to share their thinking with the class. Ideas might include: tracing the tiles, creating columns or rows of squares, or guessing.
- Explain that today you are going to practice dividing something into equal pieces.
Explicit Instruction/Teacher modeling(5 minutes)
- Demonstrate how to partition the birthday cake into pieces by creating columns and rows using the color tiles.
- Point to the columns and explain that they are called columns, a column is a number of items in a straight vertical line. Point to the rows and explain that a row is a number of things in a straight horizontal line. Explain that we use both rows and columns as a way to group something together to organize it.
- Use the think aloud strategy to show how you can determine how many rows, columns, and total number of cake pieces you have.
- Explain to the class that you have just partitioned your cake. Partition means to divide something into equal pieces.
Guided Practice(5 minutes)
- Display another blank rectangle on the projector.
- Ask your students how they could partition the rectangle using four rows and four columns.
- Have students turn and talk to a partner to share their ideas.
- Invite one or two students to come to the front of the class and demonstrate how they would partition the rectangle using the color tiles.
- Support the students by counting each row and column and helping them figure out the total number of squares in the rectangle.
- Tell the students that they will now get to practice partitioning a shape on their own.
Independent working time(15 minutes)
- Pass out the Divide It!: Rows and Columns worksheet and explain that students can use any of the math manipulatives you have provided (snap cubes, square color tiles, pre-cut paper squares, or similar material used for counting squares) to answer the questions.
- Gather a small group of students together to complete the worksheet as a group.
- Use graph paper to help students visualize the rows and columns, outline a rectangle and have students color in the squares.
- Have students complete the How Big is Your Room worksheet as an extension to this lesson.
- While students are working independently, ask them guiding questions about their work.
- How many columns are there? How many rows? How do you know? How many total squares are there? How can you double check your work?
- Collect student work samples to check for accuracy at the end of the lesson.
Review and closing(5 minutes)
- Display one or two student worksheets on the projector.
- Identify the number of columns, rows, and total number of squares on the worksheet.
- Answer any of your students' questions as needed.