Lesson 3

Fracciones no unitarias

Lesson Purpose

The purpose of this lesson is for students to understand non-unit fractions.

Lesson Narrative

Previously, students learned how to write unit fractions, using numbers of the form $$\frac{1}{b}$$. They also partitioned rectangles and used unit fractions to describe one of the parts. In this lesson, students use diagrams with multiple equal parts shaded to make sense of how non-unit fractions are made of unit fractions.

Students learn that a unit fraction is a fraction in which the numerator is 1 because it describes one of the equal-sized parts. They work with fractions that are equal to a whole number and fractions greater than a whole number to see that all non-unit fractions are built from unit fractions in the same way. Students also notice that if all the parts are shaded, then the non-unit fraction is equivalent to a whole number. The terms numerator and denominator are not used until the next section.

• Representation
• MLR8

Activity 1: Escribamos y leamos fracciones

Learning Goals

Teacher Facing

• Understand a fraction $\frac{a}{b}$ as the quantity formed by $a$ parts of size $\frac{1}{b}$.

Student Facing

• Aprendamos sobre fracciones no unitarias.

Required Materials

Materials to Copy

• Fraction Match Part 2
• Fraction Match Part 1

Required Preparation

Activity 2:

• Create a set of cards from the Fraction Match Part 1 blackline master for each group of 2.
• Create a set of 8 cards from the Fraction Match Part 2 blackline master for each group of 2.

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

How did students leverage their knowledge of unit fractions from previous lessons to make sense of non-unit fractions for the first time?

Suggested Centers

• Mystery Number (1–4), Stage 2: Three-digit Numbers (Supporting)
• Number Line Scoot (2–3), Stage 1: Twos, Fives, and Tens (Supporting)