# Lesson 1

### Lesson Purpose

The purpose of this lesson is for students to add and subtract within 10.

### Lesson Narrative

Students develop fluency with addition and subtraction within 10 in grade 1. This lesson provides an opportunity for formative assessment of students' fluency within 10, including recognizing sums with a value of 10. Throughout the lesson, monitor for the ways students find the values of sums and differences and how they describe their methods to others. There may be sums and differences students say they "just know." In this case, do not require students to explain how they got their answer every time, and take note of the expressions that many students already know from memory. Counters or connecting cubes should be made available for students to use, however encourage students not to use them if they don’t need them.

Math Community

In the lesson synthesis, students discuss what it means to be a part of a mathematical community. Prepare a space, such as a piece of poster paper, titled “Math Community”​ ​and a T-chart with the header “Doing Math” and "Norms".​ ​Partition the columns into two sections: students and teacher. The two sections encourage the students and teacher to be mindful that both respective parties are responsible for the way math is being done in the classroom. In the synthesis of this lesson, students will add their ideas to the "Doing Math" section. In upcoming lessons, students will add to and revise their contributions, including drafting classroom norms.

• Representation
• MLR8

### Learning Goals

Teacher Facing

• Add and subtract within 10.

### Student Facing

• Let’s add and subtract within 10.

### Required Materials

Materials to Gather

Materials to Copy

• Number Cards (0-10)

### Required Preparation

Activity 1:

• Create a set of number cards for each group of 2.
• The number cards will be used in upcoming lessons and thoughout the year. Consider copying the cards on cardstock or laminating them for future use.
• Create the math community poster for display in the lesson synthesis.

Building On

Building Towards

### Lesson Timeline

 Warm-up 15 min Activity 1 20 min Activity 2 10 min Lesson Synthesis 10 min Cool-down 5 min

### Teacher Reflection Questions

What do you love most about math? How are you sharing that joy with your students and encouraging them to think about what they love about math?

### Suggested Centers

• Number Puzzles: Addition and Subtraction (1–4), Stage 1: Within 10 (Supporting)