MyMathKidK-8 Curriculum

Grade 1 Number Bonds: Number Bonds Within 20

Work with all number bonds up to 20

What You'll Learn

Find missing parts for any bond within 20
Think flexibly about part-whole relationships
Connect to subtraction as finding a missing part

📖Any Number, Any Bond

Now you can break apart any number up to 20! 17 can be 10+7, or 8+9, or 11+6. There are many ways to make each number.

💡

When you need to find a missing part, think about what you know. If the whole is 16 and one part is 9, think: "What do I add to 9 to get 16?"

Worked examples

Real problems from the practice worksheets, solved one step at a time.

Example 1
4 + ? = 19
1. A number bond joins two parts to make a whole. The whole is 19 and one part is 4.
2. To find the missing part, take the known part away from the whole: 19 − 4.
3. So the missing part is 15.
Answer: 15
Example 2
? + 13 = 16
1. A number bond joins two parts to make a whole. The whole is 16 and one part is 13.
2. To find the missing part, take the known part away from the whole: 16 − 13.
3. So the missing part is 3.
Answer: 3
Example 3
2 + 16 = ?
1. A number bond joins two parts to make a whole. Here the two parts are 2 and 16.
2. To find the whole, put the parts together: 2 + 16.
3. So the whole is 18.
Answer: 18

Practice Worksheets

Number Bonds Within 20 (Set A)

Find missing parts in bonds to 20

Number Bonds Within 20 (Set B)

More practice with bonds to 20

Number Bonds Within 20 (Set C)

Additional bonds to 20 practice

Number Bonds Within 20 (Set D)

Keep practicing bonds to 20

Number Bonds Within 20 (Set E)

Master bonds within 20

Number Bonds 11-15