# Lesson 2

Situaciones de suma y resta

### Lesson Purpose

The purpose of this lesson is for students to use addition and subtraction to solve problems within 1,000.

### Lesson Narrative

Prior to this grade, students used various strategies and representations to solve problems involving addition and subtraction of multi-digit numbers (first within 100, and then within 1,000).

This lesson enables the teacher to see the strategies and representations that students use, which may include base-ten blocks or diagrams, number lines, or equations. It also elicits what students know about using place value to add or subtract (for instance, combining hundreds and hundreds, tens and tens, and ones and ones). The work here prepares students to learn algorithms for addition and subtraction, which are also grounded in the same ideas.

• Action and Expression
• MLR8

### Learning Goals

Teacher Facing

• Solve addition and subtraction problems within 1,000 in a way that makes sense to them.

### Student Facing

• Resolvamos problemas de sumas y restas.

### Required Materials

Materials to Gather

### Lesson Timeline

 Warm-up 10 min Activity 1 25 min Activity 2 10 min Lesson Synthesis 10 min Cool-down 5 min

### Teacher Reflection Questions

What strategy did you anticipate today? Which did you not anticipate?

### Suggested Centers

• Target Numbers (1–5), Stage 6: Add Hundreds, Tens, or Ones (Addressing)
• Five in a Row: Addition and Subtraction (1–2), Stage 8: Add within 1,000 with Composing (Addressing)
• Rectangle Rumble (3–5), Stage 2: Factors 1–5 (Supporting)