Lesson Plan: Estimating for 1st Grade

Objective: Students will be able to estimate the sum of two-digit numbers by using concrete models and strategies based on place value, properties of operations, and the relationship between addition and subtraction.

Materials: - Base-10 blocks (ones, tens, and hundreds) - Whiteboard or chart paper - Markers - Number cards (two-digit numbers) - Estimation worksheet

Warm-up (5 minutes): 1. Begin the lesson by reviewing place value and the concept of addition with the students. 2. Ask the students to share examples of when they estimate in their daily lives (e.g., estimating the number of candies in a jar, estimating the time it takes to complete a task). 3. Write their responses on the whiteboard or chart paper.

Introduction (10 minutes): 1. Show the students a two-digit number card (e.g., 34) and ask them to estimate what the sum would be if they added 10 to it. 2. Allow students to share their estimations and reasoning. 3. Explain that estimating means making a close guess or approximation of a number without calculating it exactly. 4. Introduce the concept of estimating sums by explaining that we can use our knowledge of place value and addition strategies to make educated guesses about the total.

Guided Practice (15 minutes): 1. Divide the students into pairs or small groups. 2. Distribute base-10 blocks to each group. 3. Give each group a two-digit number card (e.g., 56) and ask them to estimate the sum if they added 20 to it. 4. Instruct the students to use the base-10 blocks to represent the two-digit number and the additional 20. 5. Allow the students time to discuss and estimate the sum using their concrete models. 6. Have each group share their estimations and explain their reasoning to the class.

Independent Practice (15 minutes): 1. Distribute the estimation worksheet to each student. 2. Instruct the students to estimate the sum of the given two-digit numbers by using the strategies discussed. 3. Encourage the students to draw or use base-10 blocks to help them with their estimations. 4. Circulate the classroom to provide assistance and monitor student progress.

Closure (5 minutes): 1. Gather the students back together as a whole group. 2. Ask a few students to share their estimations and explain their reasoning. 3. Summarize the lesson by emphasizing the importance of estimating as a useful skill in everyday life. 4. Review the strategies and tools (place value, base-10 blocks) that can be used to estimate sums.

Assessment: - Observe students’ participation and engagement during the guided practice and independent practice activities. - Review students’ estimation worksheets to assess their understanding of estimating sums using concrete models and strategies based on place value and properties of operations.