In this Grade 5 Eureka Math lesson from Chapter 17, students learn how to add fractions with unlike denominators by creating like units numerically, moving beyond visual models to a more abstract, algebraic approach. Using problems such as adding fifths and halves, students practice finding common units and rewriting fractions before combining them. The lesson builds directly on earlier pictorial strategies to prepare students for fluent fraction addition without relying on diagrams.
Section 1
Adding Fractions with Unlike Denominators
To add fractions with unlike denominators, convert them to equivalent fractions with a common denominator, then add the numerators. A common denominator can be found by multiplying the two denominators.
Section 2
Adding Fractions Using the Least Common Denominator
To add fractions with unlike denominators, an efficient method is to find the least common multiple (LCM) of the denominators.
This LCM is the least common denominator (LCD) and is used to create equivalent fractions with the smallest possible like unit.
Expand to review the lesson summary and core properties.
Section 1
Adding Fractions with Unlike Denominators
To add fractions with unlike denominators, convert them to equivalent fractions with a common denominator, then add the numerators. A common denominator can be found by multiplying the two denominators.
Section 2
Adding Fractions Using the Least Common Denominator
To add fractions with unlike denominators, an efficient method is to find the least common multiple (LCM) of the denominators.
This LCM is the least common denominator (LCD) and is used to create equivalent fractions with the smallest possible like unit.