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Fact Families. Presentation By: Meagan Warner September 13, 2012. Overview. Today I will teach you how to master fact families I will: T each you the general guidelines for finding a fact family Show you hints and shortcuts for finding fact families
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Fact Families Presentation By: Meagan Warner September 13, 2012
Overview • Today I will teach you how to master fact families • I will: • Teach you the general guidelines for finding a fact family • Show you hints and shortcuts for finding fact families • Give you several examples so that you can practice
Basics • In fact families, there are 3 numbers organized in 4 different ways • In a family, people are related. In a fact family, numbers are related.
How to find a fact family • In finding a fact family, there will always be three numbers involved. • For example, • If the 3 numbers you are asked to find a fact family for are 2, 6, and 8, then 2, 6, and 8 will be the only numbers in your fact family. • There will also always be 2 sums and 2 differences.
Tricks for fact families • In a fact family, the biggest number will always be both of the answers to your sums.
Example • For example, • If 2, 5, and 7 are the numbers in your fact family, then 7 will be both answers to the sums. • ___ + ___ = 7 • ___ + ___ = 7
Practice • If 3, 6, and 9 are the numbers in your fact family, where do the 9’s go in your sums? • ___ + ___ = 9 • ___ + ___ = 9
Sums in Fact Families • To find your first sum, find the two smallest numbers and add them together. • Remember, your biggest number will be what the sum is set equal to. • To find the numbers that go in your second sum, reverse the numbers you used in your first sum. • For example, in the 3, 6, and 9 fact family • 3 + 6 = 9 • So… • 6 + 3 = 9
Practice • If the numbers in a fact family are 4, 5, and 9, find the sums. • 4 + 5 = 9 • 5 + 4 = 9
Tricks for fact families • The biggest number will also always be the first number for your differences.
Example • For example, • If 2, 5, and 7 are the numbers in your fact family, then 7 will be the first digit in your differences. • 7 - ___ = ___ • 7 - ___ = ___
Practice • If 3, 6, and 9 are the numbers in your fact family, where do the 9’s go in your differences? • 9 - = • 9 - =
Differences • In fact family differences, which ever number that was the answer in the first difference will be the number that you subtract from the big number. • For example, • In the 3, 6, and 9 fact family • 9 – 6 = 3 • So… • 9 – 3 = 6
Completing fact families • Find the fact family for 1, 5, and 6. • 1 + 5 = 6 • 5 + 1 = 6 • 6 – 1 = 5 • 6 – 5 = 1
Completing fact families • Find the fact family for 2, 5, and 7. • 2 + 5 = 7 • 5 + 2 = 7 • 7 – 2 = 5 • 7 – 5 = 2
Completing fact families • Find the fact family for 4, 5, and 9. • 4 + 5 = 9 • 5 + 4 = 9 • 9 – 4 = 5 • 9 – 5 = 4
Conclusion • Now you are a master of fact families. • Use what you have learned today when answering fact family questions. • And don’t forget • There will only be 3 numbers in a fact family • The biggest number will always be the answer to both of your sums • The biggest number will also always be the first number in both of your differences
Resources • http://www.bellaonline.com/articles/art57615.asp • http://mathcentral.uregina.ca/QQ/database/QQ.09.03/keisha1.html