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Number bonds and fact families

Part, part, whole: find the missing number, or write the four facts of a fact family. To 5, 10 or 20.

Updated November 7, 2026How we make our worksheets Save to Pinterest

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Why number bonds matter

Knowing that 8 and 2 make 10 is the key to adding 8 + 5 in your head: 8 + 2 + 3. Bonds and fact families make that connection visible.

Common Core standards

K.OA.A.3Split numbers up to 10 into two parts in more than one way.
K.OA.A.4Find the number that makes 10 with a given number from 1 to 9.
1.OA.B.4See subtraction as finding a missing part (10 – 7 is 7 + ? = 10).
1.OA.C.6Add and subtract within 20.

Summaries in our own words; see the Common Core State Standards for the full text.

Questions teachers ask