Unit 3, Lesson 24
Relacionemos contar con la suma y con la resta
Grado 1
Preparation
Lesson Purpose
The purpose of this lesson is for students to analyze and use counting on and taking away methods to subtract within 20.
Lesson Narrative
In a previous unit, as well as a previous section in this unit, students related addition to subtraction and thought about how knowing their addition facts to 10 could help them find differences.
The work of this lesson builds on students understanding of the relationship between addition and subtraction. In the first activity, students analyze two different methods for solving the same subtraction problem. Then they try each method with new problems. In the second activity, students find the value of the difference in subtraction equations and find the value in unknown addend equations.
- Engagement
- MLR7
- Explain (orally) strategies for finding the number that makes addition and subtraction equations true.
- Explain (orally) the subtraction strategies that take away and those that count on.
Required Materials
Required Preparation
None
Suggested Centers
NoneTeacher Reflection Questions
With which math ideas from today’s lesson did students grapple most? Did this surprise you or was this what you expected?
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