# Lesson 12

Horas, minutos y segundos

### Lesson Purpose

The purpose of this lesson is for students to use multiplication to describe the relationship between units of time and to express larger units of time in terms of smaller ones.

### Lesson Narrative

In grade 2, students learned to tell time to the nearest five minutes and recognized that there are 60 minutes in 1 hour. In grade 3, they learned to tell time to the nearest minute and to measure intervals of time. Students may also know that there are 60 seconds in a minute. In this lesson, students see the relationship between hours and minutes and between minutes and seconds in multiplicative terms. They then use their new insights to convert hours into minutes and minutes into seconds.

• Engagement
• MLR8

### Learning Goals

Teacher Facing

• Describe the multiplicative relationships between units of time.
• Express hours in terms of minutes and seconds.

### Student Facing

• Exploremos el tiempo en horas, minutos y segundos.

### Lesson Timeline

 Warm-up 10 min Activity 1 20 min Activity 2 15 min Lesson Synthesis 10 min Cool-down 5 min

### Teacher Reflection Questions

How did previewing the cool-down ahead of time help you synthesize the learning that took place in the lesson?

### Suggested Centers

• Would You Rather? (2–5), Stage 2: Compare to Smaller Units (Addressing)
• Compare (1–5), Stage 3: Multiply within 100 (Supporting)