How big do the denominators get?

Both denominators stay 6 or below, so every common denominator is 30 or less and the renaming stays mental-math sized.

Do answers need to be simplified?

Yes. The key shows every answer in simplest form, and sums past one whole print as mixed numbers like 1 1/6.

5th grade add and subtract unlike denominators

5th grade add and subtract unlike denominators worksheets

Fifth grade adds and subtracts fractions whose denominators differ. Each item pairs two proper fractions with small unlike denominators, so the work is finding a common denominator, renaming both fractions, then combining.

Free printable PDF worksheet, aligned to Common Core 5.NF.A.1.

Each print is a different sheet with its own answer key. You don't need to sign up.

The kind of problems you'll get

Simplify each answer. Write improper fractions as mixed numbers.

1/3 + 1/2
Answer: 5/6
3 1/3 − 2 5/8
Answer: 17/24
3 1/5 − 2 2/4
Answer: 7/10

Every print pulls a fresh set of problems at this level, so a make-up test or a second sibling never gets the same sheet.

What's on a 5th grade sheet

Add and subtract unlike denominators. Simplify each answer. Write improper fractions as mixed numbers. 10 problems per page.

Every version prints on US Letter or A4, with its answer key after the problems.

How to teach this

Have your child name the common denominator out loud before touching the tops. For 1/2 + 1/3, that's "sixths." Then rename each fraction completely before combining. The reliable check: whatever multiplied the bottom must multiply the top. Keep a folded paper strip nearby for halves-and-thirds pairs; seeing sixths appear beats any shortcut, and cross-multiplying tricks can wait until the renaming is automatic.

Watch for: Kids add straight across, top plus top and bottom plus bottom, turning 1/2 + 1/3 into 2/5. The denominators name the piece size, so the pieces must match before the tops can combine. Kids find the common denominator but forget to scale the numerators with it, writing 1/2 + 1/3 = 1/6 + 1/6. Whatever multiplies the bottom must multiply the top.

Common questions about 5th grade add and subtract unlike denominators

How big do the denominators get?: Both denominators stay 6 or below, so every common denominator is 30 or less and the renaming stays mental-math sized.
Do answers need to be simplified?: Yes. The key shows every answer in simplest form, and sums past one whole print as mixed numbers like 1 1/6.

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Aligned to Common Core 5.NF.A.1. Reviewed by the One more sheet team. Content version 241, updated September 2026.

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