# Lesson 3

Viene un cambio

### Lesson Purpose

The purpose of this lesson is for students to solve a new type of problem, Add To, Change Unknown. They solve the problems in a way that makes sense to them and identify the answer to a story problem in an equation.

### Lesson Narrative

In the previous lessons students wrote equations and connected them to Add To and Take From, Result Unknown story problems. Students related the numbers in the equation to the quantities in the story. They learned to draw a box around the part of the equation that answers the question in the story problem. In this lesson students are introduced to a new type of story problem where the change is unknown. Students solve in a way that makes sense to them and identify the number that represents the answer in an equation. They notice that the answer to the problem is not always the number after the equal sign.

- Action and Expression

- MLR7

Activity 1: Los libros de Kiran

### Learning Goals

Teacher Facing

- Identify the answer to a story problem in an equation.
- Solve Add To, Change Unknown story problems in a way that makes sense to them.

### Student Facing

- Resolvamos problemas-historia y encontremos la respuesta dentro de las ecuaciones.

### Required Materials

Materials to Gather

### Required Preparation

Activity 3:

- Gather materials from previous centers:
- Sort and Display, Stage 1
- Check it Off, Stages 1 and 2
- What's Behind My Back, Stage 2

### CCSS Standards

### Lesson Timeline

Warm-up | 10 min |

Activity 1 | 15 min |

Activity 2 | 10 min |

Activity 3 | 15 min |

Lesson Synthesis | 10 min |

Cool-down | 0 min |