1st Grade Adding Three Numbers Worksheet (Within 20)
Add three numbers within 20 by finding a friendly pair first — a ten or a double.
- 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
- adding three numbers within 20
- Difficulty
- Standard
- Time
- 10 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 three whole numbers with a total within 20, looking for a make-a-ten or doubles pair first.
- Adding three addends
- Finding a pair that makes ten
- Using doubles to add faster
Inside This Printable
Student directions: Add the three numbers. Find a pair that makes 10 or a double first, then add the last number.
Worked example
5 + 5 + 3: add the double 5 + 5 = 10, then 10 + 3 = 13.
Sample questions
- 2 + 3 + 4 =
- 5 + 5 + 2 =
- 4 + 1 + 6 =
The PDF contains 8 practice questions plus 2 challenge questions.
Worksheet Preview
Find a friendly pair first
Adding three numbers is easier when students remember they can add in any order. The smart first move is to look for a pair that makes ten or a double, add that, then add the last number. In 5 + 5 + 3, the double 5 + 5 = 10 makes the rest easy.
How to use it
Have students scan for a ten or a double before adding left to right. This applies the make-a-ten and doubles strategies, and leads into adding three numbers in 2nd grade.
👩🏫 Teacher note
Addition can be done in any order (1.OA.3). Teach students to scan for a ten or a double first: in 5 + 5 + 3, add the double 5 + 5 = 10, then 10 + 3 = 13.
🏠 Parent note
Look for two numbers that make 10, or a double, and add those first. Then add the last number.
Common Mistakes to Watch For
- Adding left to right and losing track
- Missing an easy pair (a ten or a double)
Answer Key
Each answer shows the total.
⬇ Download Answer Key (PDF)Learn this skill first
Take the free lesson on addition — worked examples and practice exercises, then come back to this worksheet.
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Frequently Asked Questions
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