Why do all the problems have matching denominators?

That's the fourth grade entry point. 4.NF.B.3 builds the idea that only like pieces combine. Unlike denominators get their own sheet in fifth grade.

Do answers ever go past one whole?

Not on this sheet. Sums stay within one whole, so the focus lands on combining numerators and simplifying, not on converting mixed numbers yet.

4th grade add & subtract like denominators

4th grade add & subtract like denominators worksheets

Add and subtract fractions worksheets for fourth grade keep the denominators alike in every problem, so your child can focus on the one big idea: only the numerators combine. Sums stay within one whole, and answers are written in simplest form.

Free printable PDF worksheet, aligned to Common Core 4.NF.B.3.a, 4.NF.B.3.c.

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.

1/4 + 2/4
Answer: 3/4
1/2 + 1/2
Answer: 1
3 3/6 − 2 3/6
Answer: 1

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 4th grade sheet

Add & subtract like denominators. Simplify each answer. Write improper fractions as mixed numbers. 12 problems per page.

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

How to teach this

Say each problem in words once ("three eighths plus two eighths") and it becomes obvious the answer is in eighths. Build a two-step habit: combine the tops, then ask "can it simplify?", because the second step is the one kids drop. If 5/16 shows up as an answer, that's the added-denominators error. Draw the eighths and recount.

Watch for: Kids add the bottoms too, turning 3/8 + 2/8 into 5/16. The denominator names the piece size, and the pieces don't change. Kids leave answers like 3/6 unsimplified. When the top and bottom share a factor, divide both to reach simplest form.

Common questions about 4th grade add & subtract like denominators

Why do all the problems have matching denominators?: That's the fourth grade entry point. 4.NF.B.3 builds the idea that only like pieces combine. Unlike denominators get their own sheet in fifth grade.
Do answers ever go past one whole?: Not on this sheet. Sums stay within one whole, so the focus lands on combining numerators and simplifying, not on converting mixed numbers yet.

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Aligned to Common Core 4.NF.B.3.a, 4.NF.B.3.c. Reviewed by the One more sheet team. Content version 241, updated September 2026.

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