What does my child actually write on the fix version?

The run-on prints with its period and capital missing. Your child adds both marks right on the line, and the answer key shows the corrected sentence with the added marks highlighted in green.

How do they know where to split?

Find the second part that could be a sentence on its own. In 'The cake fell the dog cheered,' that part is the dog cheered, so the period lands after fell. That hunt is the whole skill at this grade.

3rd grade run-on sentences

3rd grade run-on sentences worksheets

Run-on sentences worksheets for third grade print two sentences squeezed together with nothing between them. Your child finds where the first idea ends and writes in the missing period and capital letter. The choice version asks them to pick the correctly split sentence instead.

Free printable PDF worksheet, aligned to Common Core L.4.1.f.

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

The kind of sentences you'll fix

Each line runs two sentences together. Add the missing period and capital letter to split them.

I lost my pencil it rolled under the shelf.
Fixed: I lost my pencil. It rolled under the shelf.
The puddles froze we slid across them carefully.
We played tag nobody could catch Zoe.

Every print pulls a new set of sentences at this level, so a make-up test or a second sibling gets a different mix.

What's on a 3rd grade sheet

3rd grade sheets draw from 60 sentences, 8 to a page. 3rd and 4th grade print from the same 60 sentences. The teaching notes below are written for this grade.

A few of the sentences, as the answer key corrects them:

The soup was hot. I blew on my spoon.
The train whistled. It slowed at the crossing.
Leo built a tower. It wobbled and fell.

Fix it. Each line runs two sentences together. Add the missing period and capital letter to split them. 8 sentences to fix per page.
Choose the sentence. Circle the letter of the correctly punctuated sentence. 7 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 hunt, not the guess: find the second part that could stand alone as a sentence, and the split goes right before it. Have your child read the run-on aloud in one breath. Running out of air is the body's way of finding the missing period.

Watch for: Kids split at the first breath instead of the end of the idea. Have them find the two parts that could each stand alone as a sentence; the split goes where the second one starts. A part that opens with when, because, or if can't stand alone, so it stays attached to the sentence after it. Kids think a comma fixes a run-on. A comma alone makes a comma splice, which is still a run-on wearing a disguise. It needs a period or a comma plus a joining word.

Common questions about 3rd grade run-on sentences

What does my child actually write on the fix version?: The run-on prints with its period and capital missing. Your child adds both marks right on the line, and the answer key shows the corrected sentence with the added marks highlighted in green.
How do they know where to split?: Find the second part that could be a sentence on its own. In 'The cake fell the dog cheered,' that part is the dog cheered, so the period lands after fell. That hunt is the whole skill at this grade.

Related worksheets

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Aligned to Common Core L.4.1.f. Reviewed by the One more sheet team. Content version 241, updated October 2026.

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