Friendly Decomposition Addition

Teaching Notes

Model pairing then partial sums.

Common Mistakes

• Wrong pair total
• Incorrect decomposition.
• Forgetting remaining value.
• Misidentifying benchmark target.
• Adding partial sums incorrectly.

Differentiation

Discussion Questions

• Why is making a ten or hundred helpful?
• How does this strategy support mental math?
• When is this decomposition strategy most useful?
• Can you explain another addition strategy?

Skill Cluster

Number Sense & Operations

Estimated Time

12 minutes

Skills Practiced

Prerequisites

• 761
• 762
• Place Value Understanding
• Basic Addition Facts
• Number Bonds to 10

Next Steps

• Multi-Digit Addition Algorithms
• Compensation Strategy Addition
• Mental Math Fluency
• Decomposition Subtraction - Set A
• Breaking Apart Numbers Addition