The purpose of this lesson is for students to use subtraction methods flexibly to find differences.
Students apply their learning from the unit to flexibly use methods to subtract within 20. There is not one correct method to use, as it is based on each individual student's understanding of the concepts of subtraction and their known facts. It is helpful for students to listen to and make sense of others’ reasoning about which method they used (MP3). In the first activity, students find differences given expressions. In the second activity, students apply subtraction methods as they solve story problems with the unknown in all positions.
- Use subtraction methods flexibly to find differences based on the numbers in a given problem.
- Let’s use subtraction methods that work for the numbers in a problem.
|Activity 1||20 min|
|Activity 2||15 min|
|Lesson Synthesis||10 min|
Teacher Reflection Questions
How did your students represent their work today? How might you support them in creating more efficient representations?
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