1st Grade Addition Within 20 Worksheet
Practice addition facts with sums up to 20, with a number line to count on from the larger number.
- Homework
- Morning Work
- Centers
- Review
- Intervention
Download the Free Printable PDF
No sign-up required. Clean, low-ink US Letter format.
- Grade
- 1st Grade
- Subject
- Math
- Skill
- Addition
- Topic
- addition facts within 20
- Difficulty
- Standard
- Time
- 12 minutes
- Pages
- 2 (incl. answer key)
- Format
- Printable PDF (US Letter)
- Answer key
- Included
- Best for
- homework, morning work, centers, review, intervention
Worksheet details
What This Worksheet Practices
Students will add two numbers with sums within 20, using a number line or counting on as a strategy.
- Adding within 20
- Counting on from the larger number
- Adding across ten (e.g., 8 + 5)
Worksheet Preview
Adding within 20 with confidence
By first grade, students move past adding within 10 and start working with sums up to 20 — which means crossing the ten (like 8 + 5). The most powerful strategy at this stage is counting on from the larger number: for 3 + 9, it’s far easier to start at 9 and count on 3 than to start at 3.
How to use it
Use the number line at the top. Have your child put a finger on the larger number and hop forward the smaller number of steps. This builds the mental image of addition as movement along the number line and avoids the most common error — counting the starting number itself. Pair this with subtraction within 20 so addition and subtraction grow together.
👩🏫 Teacher note
Teach 'count on from the larger number': for 3 + 9, start at 9 and count on 3. The number line at the top makes this concrete.
🏠 Parent note
Find the bigger number on the number line, then hop forward the smaller number of steps.
Common Mistakes to Watch For
- Counting the starting number instead of counting on from it
- Losing track when crossing 10
Answer Key
Each answer shows the sum.
⬇ Download Answer Key (PDF)Part of a Practice Pack
Related Worksheets
Subtraction Within 20 Worksheet
Practice subtraction within 20, using a number line to count back or count up to the answer.
Adding Three Numbers Worksheet (Within 20)
Add three numbers within 20 by finding a friendly pair first — a ten or a double.
Addition Facts to 10 Worksheet
Practice addition facts with sums up to 10, using a number line to count on.
Christmas Addition Word Problems (Within 20)
Solve Christmas addition word problems about ornaments, gifts, and cookies, with sums up to 20.
Frequently Asked Questions
Is this worksheet free to download?
Yes. You can download and print this worksheet for free, with no sign-up required.
Does it come with an answer key?
Yes — a complete answer key is included.
Original & reviewed. Every worksheet is created in-house from a grade-level skill brief, checked for a correct answer key, and reviewed for grade-appropriateness. Our editorial policy.