Standards:

4.OA.4 Find all factor pairs for a whole number in the range 1-100. Recognize that a whole number is a multiple of each of its factors. Determine whether a given whole number in the range 1-100 is a multiple of a given one-digit number. Determine whether a given whole number in the range 1-100 is prime or composite.

Objectives:

Math Objective: I can demonstrate finding factors using area models.

Language Objective: I can describe how factors are found using area models.

Vertical Alignment:

3.OA.7 Fluently multiply and divide.

4.OA.4 Find all factor pairs for a whole number in the range 1-100. Recognize that a whole number is a multiple of each of its factors. Determine whether a given whole number in the range 1-100 is a multiple of a given one-digit number. Determine whether a given whole number in the range 1-100 is prime or composite.

Notes:

In order to be successful, students need to be familiar with area models (such as rectangular arrays) and be comfortable with the meaning of multiplication (e.g., 3 × 5 means three rows of five).

Lesson Outline:

🚀Launch:

Review area models. Show students how the numbers in the area model are the same numbers in the corresponding multiplication equation.

Here is a resource for students to use digital area models when the lesson tells them to "use squares to build one."

🤔Explore:

This lesson is for remote learning. If you are in class, you will need construction paper, grids, or blocks to make area models, and will need to follow #5-7 in the Advantage Math Lesson Plan.

Students will use a digital simulation to create as many area models for the number 24 as possible. They will share their models through pictures, video, or text.

Here are some possible questions to ask:

a. Describe how you determined the sizes of the rectangular arrays.

b. Describe how each number pair used to label the rectangular arrays relates to the number written at the top of the posters.

c. Do you see any examples of the commutative property of multiplication on the posters?

d. How could we determine if all of the possible arrays are shown?

e. Are these numbers prime or composite? How do you know?

f. What would a poster of a prime number look like? (It would only have two possible arrays: 1 × Itself & Itself × 1.)

💬Discuss

Students will find the factors of 28 and describe how they know those numbers are the factors of 28.

✅Exit Ticket

Students will answer the following question and reflect on their learning.

5.2 extit ticket problem.PNG

Additional Resources:

Digital Area Models

Differentiation:

Challenge: For students who need a challenge, during the "Independent Practice" portion of the lesson, invite students to use two handfuls of tiles (up to 100 total) to find the factors. Working with larger numbers can be more challenging than smaller numbers.

Struggling: For students who are struggling, invite them to find the factors of numbers 20 or less and become comfortable with those before moving on to numbers in the range 21–100. When students are familiar with the multiplication facts that are used as factors, they will have more success.

Student Resource #1: Learnzillion: Find all Factor Pairs using Area Models

Student Resource #2: Factor Feeder Game