Grade 2: Decomposing a Hundred to Subtract

Students use base-ten diagrams to represent subtracting within 1,000, including problems that require decomposing a hundred in this small group mini-lesson. The teacher can model how to subtract three-digit numbers by decomposing a hundred. Students then practice finding the difference by decomposing a hundred.

By Zach Wissner-Gross

Learning goals: Today's Goals • Decompose a hundred to subtract numbers within 1,000. • Language Goal: Explain why decomposing a hundred can be helpful when subtracting (Speaking and Listening). Prep Checklist • Click Project Screens to show the Teacher Presentation screen to your students. There are Teacher Moves and Sample Responses to guide this opener. • Distribute the Student Edition Paper Resource to each student. • You can launch your lesson with the Teacher Presentation screen, then transition into the Modeled Review, Guided Practice, and then Check for understanding. Use the Teacher Edition to guide instruction. Materials • Print the Student Edition Paper Resource ahead of time. • Print or review the Teacher Edition to guide instruction.