Unit 3, Lesson 8
Subtraction Algorithms (Part 1)
Grade 3
Preparation
Lesson Narrative
In previous lessons, students revisited subtraction within 1,000, using strategies based on place value, properties of operations, and the relationship between addition and subtraction. In this lesson, students are introduced to a subtraction algorithm that clearly shows the subtraction of ones from ones, tens from tens, and hundreds from hundreds, and is similar to one of the initial addition algorithms in a prior lesson. Students should have access to base-ten blocks as needed.
- Engagement
- MLR8
- Interpret (orally and in writing) the steps of a written subtraction algorithm.
- Match (orally) base-ten diagrams and algorithms that represent the same subtraction strategy.
- Let’s learn a new way to subtract.
Required Preparation
- Create a set of cards from the blackline master for each group of 2 students.
Teacher Reflection Questions
Reflect on how comfortable your students are asking questions of you and of each other. What can you do to encourage students to ask questions?