Learn on PengiEureka Math, Grade 5Chapter 23: Multiplication of a Fraction by a Fraction

Lesson 1: Multiply unit fractions by unit fractions.

In this Grade 5 Eureka Math lesson from Chapter 23, students learn to multiply unit fractions by unit fractions, building on prior work with multiplying fractions and whole numbers. Using paper folding, area models, and tape diagrams, students develop conceptual understanding of why multiplying two unit fractions like one-half by one-half yields one-fourth. The lesson connects pictorial and numerical representations to help students generalize the procedure for fraction-by-fraction multiplication.

Section 1

Multiply Unit Fractions Using an Area Model

Property

To find the product of two unit fractions, such as finding a fraction 'of' another fraction, you can multiply the denominators. The resulting product is a new unit fraction.

1a×1b=1a×b\frac{1}{a} \times \frac{1}{b} = \frac{1}{a \times b}

Examples

Lesson overview

Expand to review the lesson summary and core properties.

Expand

Section 1

Multiply Unit Fractions Using an Area Model

Property

To find the product of two unit fractions, such as finding a fraction 'of' another fraction, you can multiply the denominators. The resulting product is a new unit fraction.

1a×1b=1a×b\frac{1}{a} \times \frac{1}{b} = \frac{1}{a \times b}

Examples