Title: Adding 2-Digit Numbers within 20

Grade Level: 1st or 2nd grade

Learning Intention: Students will be able to add 2-digit numbers within 20 using various strategies.

Lesson Outline:

1. Warm-up (5 minutes):
   • Begin the lesson by reviewing the concept of addition and the symbols used (+ and =).
   • Ask students to solve a few simple addition problems mentally, such as 7 + 3, 9 + 4, and 6 + 2, to activate their prior knowledge.
2. Introduction (10 minutes):
   • Display a number line from 0 to 20 on the board or using a projector.
   • Explain that today, we will be focusing on adding 2-digit numbers within 20.
   • Discuss the importance of understanding place value and how it helps us add numbers.
   • Model how to add two-digit numbers using a number line, starting with examples where the sum is within 10 (e.g., 12 + 3, 15 + 4).
   • Emphasize the importance of breaking down the problem into tens and ones.
3. Guided Practice (15 minutes):
   • Provide students with a worksheet or individual whiteboards.
   • Give them a series of addition problems involving 2-digit numbers within 20.
   • Model and guide students through solving the problems using different strategies, such as:
     • Counting on from the larger number (e.g., 14 + 6 = 14, 15, 16, 17, 18, 19, 20).
     • Decomposing the numbers into tens and ones (e.g., 12 + 5 = 10 + 2 + 5 = 10 + 7 = 17).
     • Using a number line to visualize the addition process.
   • Monitor students’ progress and provide support as needed.
4. Independent Practice (15 minutes):
   • Distribute a set of addition word problems to each student.
   • Instruct students to read the word problems carefully and solve them independently using the strategies discussed.
   • Encourage students to show their work and explain their thinking.
   • Circulate the classroom to provide assistance and check for understanding.
5. Wrap-up (5 minutes):
   • Gather the class together and review the strategies used to add 2-digit numbers within 20.
   • Ask a few students to share their solutions and explain their thinking.
   • Summarize the lesson by emphasizing the importance of breaking down numbers and using different strategies to solve addition problems.
   • Assign a few additional practice problems for homework to reinforce the concept.

Note: This lesson plan can be modified based on the specific needs and abilities of the students. Additional resources, such as manipulatives or online interactive games, can also be incorporated to enhance the learning experience.