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🔢 Grade 1 • ➕ Addition to 20

Addition to 20 for Grade 1

📖 Lesson Grade 1 Last updated: March 2026

Addition means putting groups together to find out how many there are in all. In Grade 1, students move from counting every object one by one to using smart strategies like counting on and making 10.

What Addition Means

When we add, we join two groups together. The answer to an addition problem is called the sum.

If there are 7 toy cars on the shelf and 3 more on the floor, you can put the groups together to find the total. Addition helps us answer "How many altogether?"

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Example 7 + 3 = 10 means 7 things and 3 more things make 10 things in all.
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Tip Use the word "altogether" as a clue that you probably need addition.

Count On Instead of Starting Over

A strong Grade 1 strategy is counting on. Instead of counting every object from 1, start with the bigger number and count forward.

For 8 + 4, say "8" and then count on four more: 9, 10, 11, 12. That is faster and helps build number sense.

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Example 8 + 4 = 12 because after 8, counting on 4 more gives 9, 10, 11, 12.
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Tip Circle the larger number first so your child remembers where to start.

Use a Number Line or Make 10

A number line is a great tool for addition. Start on the first number, then hop forward.

Another smart strategy is to make 10. If you see 9 + 6, you can think: 9 needs 1 more to make 10. Take 1 from 6, so now you have 10 + 5 = 15. Making 10 helps students solve harder problems more easily.

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Example 9 + 6 = 15 because 9 + 1 = 10 and 5 more makes 15.

Solve Story Problems

Addition shows up in real life all the time. Read the story carefully and look for groups being joined together.

If Mia has 6 stickers and her friend gives her 5 more, the question is asking how many she has now. That means we add the two amounts together.

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Example Mia has 6 stickers and gets 5 more. 6 + 5 = 11 stickers.

📝 Key Vocabulary

Addition
Putting groups together to find the total
Sum
The answer to an addition problem
Number line
A line that shows numbers in order and helps us count on

📐 Standards Alignment

1.OA.A.1 CCSS.MATH

Use addition and subtraction within 20 to solve word problems.

1.OA.C.6 CCSS.MATH

Add and subtract within 20 using strategies such as counting on and making ten.

1.OA.D.7 CCSS.MATH

Understand the meaning of the equals sign and determine if equations are true or false.

🔗 Glossary Connections

⚠️ Common Mistakes to Watch For

  • Starting over at 1 instead of counting on from the first number
  • Mixing up the plus sign and the equals sign
  • Forgetting to include both groups in a story problem
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Real-World Connection Kids use addition when they count snacks, combine toy piles, add points in a game, or figure out how many crayons are in two boxes.
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Fun Fact! Many first graders learn addition facts best when they notice patterns, like doubles: 4 + 4, 5 + 5, and 6 + 6.