Unit 4, Lesson 20
Add and Subtract within 1,000,000
Grade 4
Preparation
Lesson Narrative
In this lesson, students use the standard algorithm for addition and subtraction to the hundred-thousands place. Students build their fluency with the algorithm as they encounter examples where more than one digit has to be decomposed in order to subtract. Students also look at errors that are commonly made when using the algorithm to find sums and differences.
- Action and Expression
- MLR8
- Determine (orally and in writing) errors made when adding or subtracting using the standard algorithm.
- Use the standard algorithm to add and subtract multi-digit numbers with multiple compositions or decompositions.
- Let’s use the standard algorithm to add and subtract.
Required Preparation
None
Teacher Reflection Questions
What connections did students make between the decomposition of base-ten units using expanded form and using the standard algorithm when subtracting large numbers?