2-Digit (Sum < 100)

Teaching Notes

Invite multiple solution paths and quick mental checks.

Common Mistakes

• Not aligning place values mentally.
• Forgetting to add tens after ones.
• Miscalculating regrouped values.
• Exceeding sum 100 limit.

Differentiation

Discussion Questions

• Which mental strategy worked best for you?
• How did you add the tens and ones separately?
• Can you explain your mental calculation process?
• Why is checking your answer important?

Skill Cluster

Number Sense & Operations

Estimated Time

10 minutes

Skills Practiced

Prerequisites

• 1
• Adding 1-Digit Numbers
• Place Value (Tens/Ones)
• Adding Multiples of Ten

Next Steps

• Mental Addition (Sums > 100)
• Mental Subtraction (2-Digit)
• 2-Digit (Sum > 100) - Set A
• Mental Subtraction (2-Digit) - Set A
• Making Ten Strategy - Addition