Distributive Expansion: 1-digit × 2-digit

Teaching Notes

Emphasize decomposing numbers by place value. Connect to mental math strategies.

Vocabulary

Distributive Property: Multiply a sum by multiplying each addend.

Product: The answer when two numbers are multiplied.

Common Mistakes

• Incorrect tens multiple
• Incorrect decomposition
• Error in partial product calculation
• Addition errors
• Forgetting to multiply both parts

Differentiation

Discussion Questions

• Why is breaking apart numbers helpful?
• How does this connect to mental math?
• Can we use this strategy for larger numbers?
• What properties of multiplication are we using?

Extension Activities

• Use base-ten blocks.
• Draw the expansion.
• Multiply larger numbers.

Parent Tip

Help your child break down prices like $2.50 into dollars and cents.

Skill Cluster

Number Sense & Operations

Estimated Time

12 minutes

Skills Practiced

Prerequisites

• 821
• Place Value (tens and ones)
• Basic Multiplication Facts
• Addition with Regrouping

Next Steps

• Distributive Property with Area Models
• Multiplication: 2-digit by 2-digit using partial products
• Distributive Property: Area Models
• Multiplication: 2-digit by 2-digit