# Lesson 9

Comparemos problemas-historia

### Lesson Purpose

The purpose of this lesson is for students to solve the different Put Together/Take Apart story problems that have been introduced so far.

### Lesson Narrative

Students write equations that match the story problem, identifying where the answer to the question is in the equation. Students should have access to connecting cubes or two-color counters. In Activity 1, students work with partners to solve a story problem and write an equation. During Activity 2, students do a gallery walk within their group and compare story problems, methods for solving the problems, and equations that represent the problems.

Students do not need to master representing and solving these problem types until the end of grade 2, so the important part of this lesson is that students can make sense of the story problem and explain how their equation matches the problem.

- Action and Expression

- MLR8

Activity 1: Resolvamos y representemos problemas-historia

### Learning Goals

Teacher Facing

- Solve Put Together/Take Apart problems with the result, one addend, or both addends unknown.
- Write an equation that matches the story problem, and put a box around the unknown number.

### Student Facing

- Resolvamos problemas-historia y escribamos ecuaciones.

### Required Materials

### Required Preparation

Activity 2:

- Each group will need the visual displays they created in the previous activity.

### Lesson Timeline

Warm-up | 10 min |

Activity 1 | 20 min |

Activity 2 | 20 min |

Lesson Synthesis | 10 min |

Cool-down | 0 min |

### Teacher Reflection Questions

What opportunities are you giving students to reflect on their understanding of the mathematical content?