According to the CCSSM, Kindergarten students should "fluently add and subtract within 5 (K.OA.5)" and "for any number from 1 to 9, find the number that makes 10 when added to the given number (K.OA.4)". First grade students should "apply properties of operations as strategies to add and subtract (1.OA.B.3)" and "determine the unknown whole number in an addition or subtraction equation relating three whole numbers. (1.OA.D.8)". Second graders should be able to "fluently add and subtract within 20 using mental strategies (2.OA.B.2)".

Building strong number sense is one of the most important things elementary school teachers can do to increase math fluency.

Number bonds help students see that numbers can be "broken" into pieces to make computation easier (decomposing/composing). With number bonds, students recognize the relationships between numbers through a written model that shows how the numbers are related. A number bond helps student clearly visualize the Part/Whole relationship.

Students will also see the whole on top or to the side with the parts branching down. The circles or squares are just a visual representation that students should begin with. In first grade, some students may move away from the shape visual and opt for the carrot (upside down V).

You can draw number bonds on paper using circles or bar diagrams. Even a young student who does not understand math notation can clearly see the connection between these numbers: the whole (6) has been pulled apart into two piles (4 and 2), and the piles can be pushed back together to make the whole.

Math textbooks often try to communicate the same concept using four-fact families. A four-fact family looks like this:

4 + 2 = 6
2 + 4 = 6
6 – 4 = 2
6 – 2 = 4

The idea of the four-fact family is to help students realize that once they know one of the facts in the family, they know all of them. Many students never see the connection, however, and think of these equations as separate little bits of abstract information, all of which have to be memorized. This can overload their minds and make them give up on math. On the other hand, number bonds connect to the student’s understanding at a deeper level, showing all four of the fact family relationships in a single picture.

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Included in this Worksheet set:

• Addition Number Bonds using 1-20 for each number 11-20
» Whole Number, Missing Number & Blank
• Subtraction Number Bonds Using 1-20 for each number 11-20
» Whole Number, Missing Number & Blank
• Answer Keys for Addition & Subtraction Number Bonds for each number 11-20

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Number Bonds

√ Differentiated Addition & Subtraction Number Bonds using 1-10

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Check out my other Math Fluency & Number Sense Cards:

Peeps
• Peeps Math Fluency & Number Sense Cards | English | 1-10
• Peeps Math Fluency & Number Sense Cards | Spanish | 1-10
• Peeps Math Fluency & Number Sense Cards | English | 11-20

Bunny
• Bunny Math Fluency & Number Sense Cards | English | 1-10
• Bunny Math Fluency & Number Sense Cards | Spanish | 1-10
• Bunny Math Fluency & Number Sense Cards | English | 11-20

Apple
• Apple Math Fluency & Number Sense Cards | English | 1-10
• Apple Math Fluency & Number Sense Cards | Spanish | 1-10
• Apple Math Fluency & Number Sense Cards | English | 11-20

Pumpkin
• Pumpkin Math Fluency & Number Sense Cards | English | 1-10
• Pumpkin Math Fluency & Number Sense Cards | Spanish | 1-10
• Pumpkin Math Fluency & Number Sense Cards | English | 11-20

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Looking for Fraction Work? Check these out:

• Fraction Families Charts | Math Fluency & Number Sense
• Fraction Families Charts | Color-Coded | Math Fluency & Number Sense

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Looking for Number Bond or Number Pairs work? Check these out:

• Differentiated Addition & Subtraction Number Bonds | 1-10
• Differentiated Addition & Subtraction Number Bonds | 1-20
• Differentiated Addition | Making Pairs | 1-9