# Lesson 12

Comparemos medidas

### Lesson Purpose

### Lesson Narrative

In the previous lesson, students solved Compare, Difference Unknown story problems about length measurements. Students used connecting cubes, drawings, numbers, words, or equations to solve and represent these problems. They discussed how some problems can be solved using either addition or subtraction.

In this lesson, students solve two new problem types, Compare, Bigger Unknown and Compare, Smaller Unknown, through the context of measurement and consider how a representation can be used to solve different story problems. Due to language demands of these types of problems, students will focus on Bigger Unknown versions with “more” and Smaller Unknown versions with “fewer.” Students are reintroduced to a diagram that may be helpful for Compare problems and prepares them for working with tape diagrams in grade 2.

- Representation

- MLR8

### Learning Goals

Teacher Facing

- Solve Compare story problems with unknowns in all positions.

### Student Facing

- Resolvamos problemas-historia en los que comparamos longitudes.

### Required Materials

Materials to Gather

Materials to Copy

- Write the Number Stage 3 Gameboard, Spanish

### Required Preparation

- Create a poster for the Lesson Synthesis with the problems from Activity 1 and Activity 2 and this unlabeled diagram shown two times:

Activity 3:

Put each gameboard in a sheet protector.

### 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 |