4th Grade Commas in Compound Sentences Worksheets

A compound sentence joins two complete thoughts with a coordinating conjunction (and, but, or, so, yet), and a comma marks the seam: the bell rang, but nobody moved. Fourth graders learn to test each half, and if both could stand alone as sentences, the comma goes before the joining word.

Free printable PDF, aligned to Common Core L.4.2.c. One skill per page, answer key on page two.

Every sheet is one of a kind and prints with a version code, so you can reprint the exact same one later. New version every click.

The kind of sentences you'll fix

Add the missing comma to each sentence.

Clouds hid the peak but we kept climbing.
Fixed: Clouds hid the peak, but we kept climbing.
The trail looked short but it climbed forever.
It rained all day so we read inside.

Every print draws a fresh mix of sentences at this level, so a make-up test or a second sibling gets a different sheet.

What's on each sheet

Fix it. Add the missing comma to each sentence. 8 sentences to fix per page.
Choose the sentence. Circle the letter of the sentence with the comma in the right place. 8 questions per page.

Every version prints on US Letter or A4, with its answer key on the last page.

How to teach this

Teach the two-thumbs test: cover each half of the sentence and ask whether it could stand alone. Two yeses mean a comma before the conjunction. The wrong option with the comma after the conjunction (rained so, we) reads strangely aloud, so hearing the options is a dependable check.

Watch for: The comma goes before the conjunction, never after it: rained, so we (not rained so, we). If the second half can't stand alone (I ran and jumped), no comma is needed.

Common questions about commas in compound sentences

When does "and" need a comma before it?: When it joins two complete sentences: Dad cooked dinner, and I washed the dishes. Each half stands alone. If the second part can't stand by itself (Dad cooked dinner and hummed), no comma is needed. The stand-alone test settles every case.
What are the joining words to watch for?: And, but, or, so, and yet are the ones on these worksheets; teachers often add for and nor to complete the famous FANBOYS set. Whichever conjunction appears, the comma's place never changes: right before it, never after.

Related worksheets

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Aligned to Common Core L.4.2.c. Reviewed by the One More Sheet curriculum team. Content version 68, updated July 2026.