Unit 4, Lesson 18
Algoritmo estándar para sumar y restar
Grado 4
Preparation
Lesson Purpose
The purpose of this lesson is to add and subtract large numbers within 100,000 using the standard algorithm.
Lesson Narrative
In IM Grade 3, students found sums and differences within 1,000. Students analyzed and used different algorithms based on place value, including the standard algorithm. As students work with larger numbers in IM Grade 4, they recognize that the standard algorithm is a reliable and efficient way to add and subtract within 1,000,000.
Grid paper should be made available but not required, as a tool to support aligning digits when adding and subtracting in each activity.
- Representation
- MLR2
- Compare and contrast (orally) written methods for adding and subtracting multi-digit numbers.
- Comprehend (in spoken language) the meaning of the term “standard algorithm.”
- Use the standard algorithm to add and subtract (without decomposing) multi-digit numbers.
Required Preparation
None
Teacher Reflection Questions
What strategies from earlier grades did students rely on to find sums and differences in the Warm-up and first activity, before the standard algorithm was explicitly mentioned? How can you support students in connecting these strategies to the standard algorithm?
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