This lesson is a Number Talk that focuses on 2.NBT.B.5 and 2.NBT.B.6 - adding three 2-digit numbers using mental strategies. The teacher poses a word problem orally, and students are given time to find a sum. Students share their thinking strategies with a partner, and then three students chart and explain their thinking with the whole group.
The video is annotated using the Instructional Practice Guide: Coaching Tool.
Number Talk/Mental Computation (Frakes)Download
The teacher allows students to share their thinking with a partner, giving them sentence stems to frame the conversation. In doing this, the teacher creates opportunities for students to listen to a peer's strategy to deepen his/her own mathematical understanding.
This lesson targets students' procedural skill and fluency in adding three 2-digit numbers. The students shown use strategies based on place value and properties of operations in their explanations, aligning with 2.NBT.B: Use place value understanding and properties of operations to add and subtract.
Three students come up to explain their thinking strategies to the whole group. Each of the three students uses a different solution method to find the answer, allowing students to make connections and strengthen their levels of understanding in multiple ways.
Students are in charge of the learning during this lesson - each of the three students that come up are able to explain their thinking clearly with minimal prompting from the teacher. Based on student attentiveness, it is evident that this is a consistent classroom routine that is embedded into the classroom culture.