Learn on PengiEureka Math, Grade 4Chapter 23: Fraction Comparison

Lesson 3: Find common units or number of units to compare two fractions.

In this Grade 4 Eureka Math lesson from Chapter 23: Fraction Comparison, students learn how to compare two fractions by finding common units or a common number of units, using strategies such as area models and unit language. Students practice reasoning about fraction size by identifying whether denominators or numerators match, then applying benchmark fractions and number lines to order fractions with unrelated denominators. This lesson builds on prior work with equivalent fractions and prepares students to make precise comparisons using the greater than, less than, and equal to symbols.

Section 1

Comparing Fractions with the Same Denominator

Property

To compare two fractions with the same denominator, compare their numerators.
The fraction with the greater numerator is the greater fraction.
If a>ca > c, then ab>cb\frac{a}{b} > \frac{c}{b}.

Examples

Section 2

Comparing Fractions with Like Numerators

Property

When two fractions have the same numerator, the fraction with the smaller denominator is greater because its pieces are larger.
If a>0a > 0 and b>c>0b > c > 0, then ab<ac\frac{a}{b} < \frac{a}{c}.

Examples

Section 3

Choosing a Fraction Comparison Strategy

Property

To efficiently compare two fractions, choose a strategy by checking for relationships:

  1. Common Denominator: Use when denominators are the same or one is a multiple of the other.
  2. Common Numerator: Use when numerators are the same or one is a multiple of the other.
  3. Benchmark Comparison: Use when one fraction is clearly greater than a benchmark (like 12\frac{1}{2}) and the other is clearly less.

Examples

Book overview

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Chapter 23: Fraction Comparison

  1. Lesson 1

    Lesson 1: Reason using benchmarks to compare two fractions on the number line.

  2. Lesson 2

    Lesson 2: Reason using benchmarks to compare two fractions on the number line.

  3. Lesson 3Current

    Lesson 3: Find common units or number of units to compare two fractions.

  4. Lesson 4

    Lesson 4: Find common units or number of units to compare two fractions.

Lesson overview

Expand to review the lesson summary and core properties.

Expand

Section 1

Comparing Fractions with the Same Denominator

Property

To compare two fractions with the same denominator, compare their numerators.
The fraction with the greater numerator is the greater fraction.
If a>ca > c, then ab>cb\frac{a}{b} > \frac{c}{b}.

Examples

Section 2

Comparing Fractions with Like Numerators

Property

When two fractions have the same numerator, the fraction with the smaller denominator is greater because its pieces are larger.
If a>0a > 0 and b>c>0b > c > 0, then ab<ac\frac{a}{b} < \frac{a}{c}.

Examples

Section 3

Choosing a Fraction Comparison Strategy

Property

To efficiently compare two fractions, choose a strategy by checking for relationships:

  1. Common Denominator: Use when denominators are the same or one is a multiple of the other.
  2. Common Numerator: Use when numerators are the same or one is a multiple of the other.
  3. Benchmark Comparison: Use when one fraction is clearly greater than a benchmark (like 12\frac{1}{2}) and the other is clearly less.

Examples

Book overview

Jump across lessons in the current chapter without opening the full course modal.

Continue this chapter

Chapter 23: Fraction Comparison

  1. Lesson 1

    Lesson 1: Reason using benchmarks to compare two fractions on the number line.

  2. Lesson 2

    Lesson 2: Reason using benchmarks to compare two fractions on the number line.

  3. Lesson 3Current

    Lesson 3: Find common units or number of units to compare two fractions.

  4. Lesson 4

    Lesson 4: Find common units or number of units to compare two fractions.