Arithmetic Grade One

Lesson One hundred three: Fact Families


Fact Families

	7, 5, 12

	7 + 5 = 12
	5 + 7 = 12
	12 - 5 = 7
	12 - 7 = 5


6, 1, 7 6 + 1 = 7 1 + 6 = 7 7 - 1 = 6 7 - 6 = 1

NOTE: Explain that a fact family is a set of three numbers like the examples shown on this page. Have the student write out the equations for the following fact families as practice: (3,4,7), (8,1,9), and (2,3,5). If the student has difficulty, guide the student through these practice examples and create a couple more examples for the student. Explain that a fact family always has two addition statements and two subtraction statements. Sometimes a fact family will contain duplicate numbers like this example: (2,2,4). Fact families are so important that the next assignment will also deal with them.
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