Title: Exploring Addition and Subtraction within 40

Grade Level: 1st Grade

Objective: - Students will understand the concept of addition and subtraction within 40. - Students will be able to solve addition and subtraction problems within 40 using various strategies. - Students will develop fluency in mental math and number sense.

Materials: - Math in Focus Chapter 6 Numbers to 40 textbook - Whiteboard or chart paper - Markers or chalk - Manipulatives (e.g., counters, cubes, or number cards) - Worksheet with addition and subtraction problems within 40

Lesson Plan:

Introduction (5 minutes): 1. Begin the lesson by reviewing the concept of addition and subtraction. 2. Ask students to share examples of addition and subtraction problems they have encountered in their daily lives. 3. Explain that today, we will focus on solving addition and subtraction problems within 40.

Exploration (15 minutes): 1. Distribute manipulatives to each student or group. 2. Display a number line from 0 to 40 on the whiteboard or chart paper. 3. Model how to solve addition problems within 40 using the number line. For example, 15 + 8 = ___. Start at 15 on the number line and count 8 spaces forward to find the sum. 4. Allow students to practice solving addition problems using the number line and manipulatives. Circulate the classroom to provide support and guidance as needed.

Guided Practice (10 minutes): 1. Write a few addition problems on the board, such as 23 + 9, 35 + 6, and 18 + 12. 2. Solve the first problem together as a class, using the number line or manipulatives. 3. Ask students to solve the remaining problems independently or in pairs, using their preferred strategy. 4. Review the answers as a class, discussing different strategies used by students.

Direct Instruction (10 minutes): 1. Introduce the concept of subtraction within 40. 2. Model how to solve subtraction problems using the number line. For example, 32 - 9 = ___. Start at 32 on the number line and count 9 spaces backward to find the difference. 3. Provide additional examples and guide students through the process of solving subtraction problems using the number line or manipulatives.

Independent Practice (10 minutes): 1. Distribute a worksheet with a variety of addition and subtraction problems within 40. 2. Instruct students to solve the problems independently, using their preferred strategy. 3. Encourage students to check their work using manipulatives or the number line. 4. Collect the worksheets for assessment purposes.

Conclusion (5 minutes): 1. Review the strategies used to solve addition and subtraction problems within 40. 2. Ask students to share any challenges they encountered and how they overcame them. 3. Summarize the importance of fluency in mental math and number sense. 4. Provide positive feedback and reinforce the concept of continuous practice to improve math skills.

Extension Activity: 1. Create a math center with various addition and subtraction word problems within 40. 2. Encourage students to work in pairs or small groups to solve the problems using manipulatives, number lines, or mental math. 3. Rotate the center regularly to provide ongoing practice and reinforcement.