# Lesson 9

Relate Area to Multiplication

### Lesson Purpose

### Lesson Narrative

Students build on their understanding of multiplication and area from grade 3 as they work with areas with fractional side lengths. Students may count the number of smaller parts within a rectangle and will need to recognize and consider the size of these parts, which is a fraction of a square unit. It is important to be precise in the units used to describe the area and teachers should make sure to refer to “square units” rather than “squares.”

As with the area work in grade 3, the commutative property may come up. The commutative property allows students to find products in a way that makes sense to them. For example a student might find the area of a rectangle with side lengths \(\frac{1}{2}\) and 4 by thinking of 4 groups of \(\frac{1}{2}\).

In Unit 6, students have another opportunity to interpret the product of a fraction and a whole number in the context of multiplication as scaling. This section is about area.

- Action and Expression

- MLR8

### Learning Goals

Teacher Facing

- Find the area of a rectangle with a unit fraction side length in a way that makes sense to them.

### Student Facing

- Let’s explore the area of rectangles with one side length that is a unit fraction.

### Required Materials

Materials to Copy

- Grid Paper 5

### Required Preparation

### CCSS Standards

Addressing

### Lesson Timeline

Warm-up | 10 min |

Activity 1 | 15 min |

Activity 2 | 20 min |

Lesson Synthesis | 10 min |

Cool-down | 5 min |

### Teacher Reflection Questions

### Suggested Centers

- Target Measurements (2–5), Stage 5: Fractions of Angles (Addressing)
- How Close? (1–5), Stage 6: Multiply to 3,000 (Supporting)

### Print Formatted Materials

Teachers with a valid work email address can click here to register or sign in for free access to Cool Down, Teacher Guide, and PowerPoint materials.

Student Task Statements | docx | |

Lesson Cover Page | docx | |

Cool Down | Log In | |

Teacher Guide | Log In | |

Teacher Presentation Materials | docx | |

Blackline Masters | zip |