# Lesson 18

Lots of Fractions to Add

### Lesson Purpose

The purpose of this lesson is for students to find the sum of three or more tenths and hundredths.

### Lesson Narrative

Previously, students learned to find sums of fractions with the same denominator and sums of tenths and hundredths. They added two or more tenths and hundredths, applying the commutative and associative properties along the way. This lesson prompts students to apply their understanding and skills to solve problems in context, and to practice finding sums of three or more tenths and hundredths (including mixed numbers).

- Representation

- MLR8

### Learning Goals

Teacher Facing

- Find the sum of three or more tenths and hundredths, using the commutative and associative properties strategically.

### Student Facing

- Let’s add tenths and hundredths again, more than two at a time.

### Required Materials

### Required Preparation

Activity 1:

- Gather a few coins of different thicknesses for display.

Activity 2:

- Create six posters with an addition expression from the activity on each one.

### CCSS Standards

### 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

As you finish up this unit, reflect on the norms and activities that have supported each student in learning math. List the ways you have seen each student grow as a young mathematician throughout this work. List the ways you have seen yourself grow as a teacher. What will you continue to do and what will you improve upon in Unit 4?

### Suggested Centers

- Compare (1–5), Stage 6: Add and Subtract Fractions (Addressing)
- Rolling for Fractions (3–5), Stage 2: Multiply a Fraction by a Whole Number (Addressing)
- Compare (1–5), Stage 3: Multiply within 100 (Supporting)

### Print Formatted Materials

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Student Task Statements | docx | |

Lesson Cover Page | docx | |

Cool Down | Log In | |

Teacher Guide | Log In | |

Teacher Presentation Materials | docx | |

Blackline Masters | zip |