Unit 7, Lesson 3
Count On or Count Back to Subtract
Grade 2
Preparation
Lesson Narrative
In previous units, students used counting on or counting back to subtract within 100. In this lesson, they analyze different methods, including counting on and counting back, to subtract within 1,000. They make connections between sums of 10 and sums of 100, for example and . Students use the relationship between addition and subtraction as they find unknown values in subtraction and addition equations.
- Engagement
- MLR8
- Explain (orally) strategies for subtracting and strategies for finding the value of an unknown addend within 1,000.
- Interpret (orally) representations of subtraction strategies that show taking away tens and ones and those that show counting by place value.
- Let’s find the difference between numbers.
Required Materials
Activity 1
Required Preparation
None
Teacher Reflection Questions
What strategies are students using to subtract? How can you help students see the connections between addition and subtraction as they consider ways to subtract within 1,000?