Adding whole hundreds (3 addends)

Teaching Notes

Combines multiple addends with place value understanding. Strategy: Think about the hundreds digit only (2+3+4=9), then add zeros. This reinforces that place value rules apply consistently across all positions.

Vocabulary

Whole hundreds: Numbers like 100, 200, 300, ending in two zeros.

Place value: The value of a digit based on its position.

Common Mistakes

• Mixing up place values
• Adding only two of three numbers
• Writing 90 instead of 900
• Forgetting to include all addends
• Forgetting to write the two zeros in the hundreds place, resulting in answers like '6' instead of '600'.
• Confusing adding hundreds with adding tens or ones without proper place value understanding.

Differentiation

Discussion Questions

• How is adding 100 + 200 + 300 like adding 1 + 2 + 3?
• Why is understanding place value important when adding hundreds?
• Can you think of a time outside of school when you might need to add hundreds?

Extension Activities

• Add 4 whole hundreds.
• Add whole thousands.
• Use base-ten blocks.

Parent Tip

Ask your child to count by hundreds up to 1000.

Skill Cluster

Number Sense & Place Value

Estimated Time

15 minutes

Skills Practiced

Prerequisites

• Counting by hundreds to 1000
• Understanding place value (hundreds, tens, ones)
• Basic addition facts within 20

Next Steps

• Adding 3-digit numbers without regrouping
• Mentally adding or subtracting 100 from a number
• Estimating sums of 3-digit numbers