In this Grade 5 Illustrative Mathematics lesson from Chapter 6, students learn to add and subtract fractions with unlike denominators by finding common denominators, including cases where one denominator is a multiple of the other and cases requiring a new common denominator. Students use fraction strips and number lines to represent equivalent fractions and reason through sums and differences such as 5/6 − 1/3 and 3/4 + 1/2. This lesson addresses standard 5.NF.A.1 and builds on prior knowledge of same-denominator fraction operations from earlier grades.
Section 1
Defining a Fraction and Its Whole
A fraction represents a part of a whole that has been divided into equal parts.
The 'whole' can be a single object or a quantity, such as length, area, mass, or volume.
A unit fraction, , represents one of these equal parts.
Section 2
Identifying Equivalent Fractions Using Area Models
Equivalent fractions represent the same portion of a whole.
You can generate an equivalent fraction by multiplying the numerator and the denominator by the same non-zero number, which corresponds to partitioning an area model into smaller equal pieces.
Section 3
Adding and Subtracting Like Fractions
Fractions that have the same denominator are called like fractions.
To add (or subtract) two like fractions:
Section 4
Adding Unlike Fractions to Get an Improper Fraction
To add fractions with unlike denominators, find a common denominator, convert them to equivalent fractions, and add the numerators.
The sum is an improper fraction if it is greater than 1.
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Section 1
Defining a Fraction and Its Whole
A fraction represents a part of a whole that has been divided into equal parts.
The 'whole' can be a single object or a quantity, such as length, area, mass, or volume.
A unit fraction, , represents one of these equal parts.
Section 2
Identifying Equivalent Fractions Using Area Models
Equivalent fractions represent the same portion of a whole.
You can generate an equivalent fraction by multiplying the numerator and the denominator by the same non-zero number, which corresponds to partitioning an area model into smaller equal pieces.
Section 3
Adding and Subtracting Like Fractions
Fractions that have the same denominator are called like fractions.
To add (or subtract) two like fractions:
Section 4
Adding Unlike Fractions to Get an Improper Fraction
To add fractions with unlike denominators, find a common denominator, convert them to equivalent fractions, and add the numerators.
The sum is an improper fraction if it is greater than 1.
Book overview
Jump across lessons in the current chapter without opening the full course modal.
Continue this chapter