Lesson Plan:

# Multiplication: Solving for Unknown Factors

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Subject
Standards
August 24, 2015

## Learning Objectives

Students will be able to solve for the unknown factor in multiplication problems.

## Lesson

### Introduction (10 minutes)

• Tell your students that today they are going to learn strategies for solving for the unknown factor involving multiplication problems.
• As the students share, list the strategies on the board. Your students might offer suggestions such as repeated subtraction or arrays.

### Explicit Instruction/Teacher Modeling (15 minutes)

• Write a few multiplication problems on the board with an unknown factor. For example, 6 x ____ = 36.
• Have your students rewrite the problem as a division problem, as follows: 36 รท 6 = _____.
• Ask your students to choose an effective division strategy that they know.
• Solve the problem using repeated subtraction: 36-6=30-6=24-6=18-6=12-6=6-6=0.
• Then, show your students how to solve the problem using arrays or grouping: XXXXXX XXXXXX XXXXXX XXXXXX XXXXXX XXXXXX

### Guided Practice/Interactive Modeling (15 minutes)

• Have your students solve _____ X 5 = 40 using what they think is the most efficient strategy.
• Ask for volunteers to raise their hands and share with the class the steps to solve the problem.
• As the problem is being solved aloud, write down the steps on the whiteboard.
• When the problem is done, review it with the class for accuracy.

### Independent Working Time (15 minutes)

• Give the students the Solve the Unknown Factor worksheet to complete.

## Extend

### Differentiation

• Enrichment: Have your students skip the division step on their papers to solve the multiplication problems. Encourage them to memorize multiplication facts to quickly solve problems.
• Support: Give your students simpler problems to solve, such as 3 x ___ = 12. Use manipulatives to help show grouping and arrays.

## Review

### Assessment (10 minutes)

• Walk around and observe the students as they work on completing the assignment.
• Monitor the students as they work, making sure that the problems are done correctly.