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Printable Adding Fractions with Unlike Denominators in PDF: Step-by-Step Worksheets

These free printable worksheets give grade 5 students step-by-step practice adding fractions that have different denominators. Each worksheet mixes multiple-choice and free-response questions, and every worksheet includes an answer key so students can check their own work.

Before adding, students first need to find a common denominator between the two fractions, then add the numerators once the denominators match. For more fraction practice, explore Brighterly’s fractions worksheets hub.

Adding Fractions with Unlike Denominators Worksheets: Free Download

Get started with these grade 5 worksheets today. Click the link below to download the free PDF, which can be printed and used at home or in school, or completed digitally in a tutoring session.

How to Add Fractions with Unlike Denominators

When two fractions have different denominators, the numerators can’t be added directly — the pieces are different sizes until the denominators match. Follow these steps:

1. Find the least common denominator (LCD) of the two different fractions. This is usually the least common multiple of the two denominators.
2. Convert each fraction to an equivalent fraction with that denominator.
3. Add the numerators together and keep the denominator the same.
4. Simplify the result if possible.

Worked Example 1: 3/4 + 1/2

• The denominators are 4 and 2. The least common denominator is 4.
• Convert 1/2 to an equivalent fraction with denominator 4: 1/2 = 2/4.
• Add: 3/4 + 2/4 = 5/4.
• Simplify: 5/4 = 1¼.

3/4 + 1/2 = 1¼

Worked Example 2: 1/3 + 1/4

• The denominators are 3 and 4. The least common denominator is 12.
• Convert: 1/3 = 4/12 and 1/4 = 3/12.
• Add: 4/12 + 3/12 = 7/12.

1/3 + 1/4 = 7/12

Alternative Method: Multiply the Denominators

Another way to add fractions with unlike denominators, without finding the LCD first, is to multiply the two denominators together, multiply each numerator by the opposite denominator, and then add the results. This works well as a quick check alongside the common denominator method above.

• Multiply the denominators: 3 × 4 = 12
• Multiply each numerator by the opposite denominator: 1 × 4 = 4 and 1 × 3 = 3
• Add the results: 4/12 + 3/12 = 7/12

This matches the answer from Worked Example 2, confirming that both methods lead to the same result.

More Fractions Worksheets

Once your child is confident adding fractions with unlike denominators, explore more of Brighterly’s fractions practice:

• Common Denominator Worksheets
• Least Common Multiple Worksheets
• Equivalent Fractions Worksheets
• Adding Fractions with Like Denominators Worksheets
• Subtracting Fractions with Unlike Denominators Worksheets
• 5th Grade Fractions Worksheets
• 4th Grade Math Worksheets
• 5th Grade Math Worksheets

What Kids Practice With These Adding Fractions Worksheets

• Finding the least common denominator between two fractions
• Converting fractions to equivalent forms with matching denominators
• Adding numerators and simplifying the result
• Answering both multiple-choice and free-response fraction problems
• Checking work against an included answer key

Each worksheet includes an answer key, so students can check their own results without waiting for a teacher to grade the page. Practicing both the common-denominator method and the multiply-the-denominators method gives students more than one way to solve the same type of problem.

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FAQ

How do you add fractions with unlike denominators?

First find the least common denominator of the two fractions, then convert each fraction to an equivalent fraction with that denominator. Once both fractions share the same denominator, add the numerators together and keep the denominator the same, then simplify the result if the numerator and denominator share a common factor.

What grade is this adding fractions worksheet for?

This worksheet is written for grade 5 students who are building on earlier fraction skills like identifying fractions and finding common denominators. Problems mix multiple-choice and free-response formats, matching the level where most fifth graders practice adding fractions with unlike denominators in class, right before moving on to subtracting them the same way.

What’s the difference between finding the LCD and multiplying the denominators?

Finding the least common denominator uses the smallest shared multiple of the two denominators, which usually keeps the numbers smaller. Multiplying the denominators together always works too, but it can produce a larger denominator that needs to be simplified afterward. Both methods lead to the same final answer when done correctly.

Does this worksheet include an answer key?

Yes, this worksheet includes an answer key at the end of the document. Students can check their own results as soon as they finish a problem, which helps them catch mistakes in finding a common denominator or adding numerators right away, instead of waiting for a teacher to grade the assignment.

Is this worksheet free and printable?

Yes, this worksheet is free to download as a printable PDF, and no account or sign-up is required. Families can print the pages for hands-on practice with a pencil and paper, or complete the problems digitally during a tutoring session if a printer isn’t available, since the questions work equally well either way.