# Lesson 1

Sums I Know

### Lesson Purpose

The purpose of this lesson is for students to identify which sums within 10 they know and which they are still working on.

### Lesson Narrative

In a previous unit, students practiced adding and subtracting within 10, with an emphasis on adding or subtracting 1 and 2. They also considered the commutative property in the context of story problems. Students classify sums as “got it” or “not yet” depending on whether they know the sum quickly or not. There is not a specific time expectation for students to classify sums as “got it,” but class discussion allows students to consider what it means to “get” the sum. Students discuss ways of finding sums within ten that they don’t know yet.

As students find sums, they may count on, know some sums from memory, apply the commutative property and use related sums. Students work towards the end-of-year fluency goal for grade 1 which requires demonstrating fluency for adding and subtracting within 10. Fluency is defined as being efficient, flexible, and accurate.

Expression cards are cut out by students during this lesson, but can be prepared ahead of time if preferred. The cards students make will be used throughout the unit in lesson and center activities.

• Engagement
• MLR8

### Learning Goals

Teacher Facing

• Identify known sums within 10.

### Student Facing

• Let’s see which sums within 10 we know.

### Required Materials

Materials to Gather

Materials to Copy

• Compare Stage 1 Addition Cards to 10

Building Towards

### Lesson Timeline

 Warm-up 10 min Activity 1 15 min Activity 2 25 min Lesson Synthesis 10 min Cool-down 0 min

### Teacher Reflection Questions

Fluency is defined as being efficient, flexible, and accurate. How is this definition different than your previous understanding of fluency? How will it change the way you assess student fluency of addition and subtraction within 10?

### Print Formatted Materials

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