Grade 3 · Literacy

Grammar & Writing Conventions Activities for Grade 3

Grade 3 grammar instruction moves beyond basic punctuation to more sophisticated conventions that improve writing clarity and style. The Ontario Language curriculum emphasizes comma usage in series and compound sentences, subject-verb agreement, and an understanding of how sentences can be combined and varied for effect. At this stage, students should be writing longer pieces and need these tools to communicate clearly. Grammar instruction should connect directly to students' own writing—errors become teaching opportunities, and conventions are presented as tools for clearer communication, not arbitrary rules. The goal is helping students internalize conventions so they can focus on content while writing, then refine mechanics during editing.

Ontario Curriculum Expectations

  • Use commas correctly in a series and after introductory words
  • Maintain subject-verb agreement in writing
  • Write increasingly complex sentences using conjunctions
  • Use correct capitalization for proper nouns, titles, and sentence beginnings
  • Edit and proofread writing for grammar, spelling, and punctuation

Classroom Activities

Comma Series Challenge

15-20 minutes
Materials Needed:
Sentence strips · Comma cards · List-making prompts

Steps:

  1. Review the rule: when listing 3 or more items, separate with commas (include Oxford comma)
  2. Show sentences: 'I need bread butter and milk' - Where do commas go?
  3. Students add commas to sentence strips
  4. Create fun lists: 'In my dream vacation, I would visit ___, ___, and ___.'
  5. Students write 3 sentences with series, then trade and check with partners
Differentiation: Start with lists of words before embedding in sentences. For advanced students, introduce sentences where commas change meaning ('Let's eat, Grandma!' vs. 'Let's eat Grandma!').

Subject-Verb Agreement Detectives

20 minutes
Materials Needed:
Sentences with agreement errors · Subject/Verb matching cards · Detective notebooks

Steps:

  1. Explain: The subject (who/what) and verb (action) must 'agree' - singular with singular, plural with plural
  2. Model: 'The dogs runs.' - Dogs is plural, so we need 'run' not 'runs'
  3. Students identify subjects and verbs in sentences using different colors
  4. Practice with tricky subjects: 'The group of students (is/are) ready' (group = singular)
  5. Error hunt: Find and fix agreement errors in a paragraph
Differentiation: Use simple sentences (The cat runs. The cats run.) before complex ones. For advanced students, introduce compound subjects and collective nouns.

Sentence Combining Workshop

25 minutes
Materials Needed:
Simple sentence pairs · Conjunction word bank · Combined sentence templates

Steps:

  1. Show two simple sentences: 'I like pizza. I don't like mushrooms on it.'
  2. Introduce FANBOYS (for, and, nor, but, or, yet, so) and when to use each
  3. Model combining: 'I like pizza, but I don't like mushrooms on it.'
  4. Students practice combining 5 sentence pairs using different conjunctions
  5. Discuss how combining creates more sophisticated writing
Differentiation: Provide a conjunction choice for each sentence pair. Advanced students create their own simple sentences to combine and experiment with different conjunctions.

Differentiation & IEP Supports

Create personal grammar reference cards students keep at their desks
Use mentor texts to show conventions in action
Allow verbal editing conferences before written corrections
Break editing into focused passes: first capitals, then punctuation, then spelling
Color-code parts of speech to make agreement visual
For IEP students, focus on high-impact conventions that affect meaning

Assessment Ideas

  • Editing assessments with paragraphs containing 5-8 errors
  • Grammar skills checklist tracked across writing samples
  • Sentence combining quizzes with multiple correct answers accepted
  • Writing sample rubric with conventions as one criterion
  • Student-led editing conferences with evidence of self-correction
  • Error analysis: tracking pattern of individual student errors over time

Frequently Asked Questions

My Grade 3 students write run-on sentences constantly. How do I fix this?
Run-ons usually happen because students have lots to say! Teach them to listen for 'thought breaks' where one complete idea ends. Practice reading run-ons aloud and clapping at natural breaks. Teach the three fixes: period (new sentence), comma + conjunction, or semicolon (Grade 3 students usually stick with the first two).
How much grammar should I teach explicitly vs. through writing?
Both matter. Short explicit mini-lessons (5-10 minutes) introduce concepts. Then students immediately apply in their own writing. When you see common errors across student work, that signals a need for whole-class instruction. Individual errors are best addressed in writing conferences. Always connect rules to real writing.
Do I need to teach all parts of speech in Grade 3?
Focus on nouns, verbs, and adjectives—these directly impact writing quality. Pronouns matter for agreement and avoiding repetition. Adverbs can be introduced simply. Don't get caught up in extensive parts of speech drills. Students should understand how words function to improve their writing, not just label them.
How do I help students remember comma rules?
Focus on the most common uses: series (lists), compound sentences (before FANBOYS joining two complete sentences), and after introductory words. Create anchor charts and personal reference cards. Practice with authentic writing, not just worksheets. When students understand that commas help readers, they're more motivated to use them correctly.
Should spelling be part of grammar instruction?
Spelling is a separate skill from grammar (conventions of written language), but both matter for clear writing. Teach spelling through word study patterns, not just memorization. During editing, students should check both grammar and spelling. Some students excel at one but struggle with the other—differentiate accordingly.

Related Resources

Grade 2 Grammar & Writing Conventions Grade 3 Reading Comprehension

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