Learn on PengienVision, Mathematics, Grade 4Chapter 9: Understand Addition and Subtraction of Fractions

Lesson 4: Model Subtraction of Fractions

Property.

Section 1

Model Subtracting a Fraction from One on a Number Line

Property

To subtract a fraction from one whole, first rename 1 as a fraction with the same denominator as the fraction being subtracted.
Then, subtract the numerators.

1 - \frac{a}{b} = \frac{b}{b} - \frac{a}{b} = \frac{b-a}{b}

Examples

Section 2

Model Fraction Subtraction with Area Models

Property

To subtract fractions with like denominators using an area model, first shade the parts for the starting fraction (the minuend).
Then, cross out the number of parts being subtracted (the subtrahend).
The number of remaining shaded parts represents the difference.

Examples

Lesson overview

Expand to review the lesson summary and core properties.

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Section 1

Model Subtracting a Fraction from One on a Number Line

Property

To subtract a fraction from one whole, first rename 1 as a fraction with the same denominator as the fraction being subtracted.
Then, subtract the numerators.

1 - \frac{a}{b} = \frac{b}{b} - \frac{a}{b} = \frac{b-a}{b}