2009 Standard of Learning- 2.9

The student will recognize and describe the related facts that represent and describe the inverse relationship between addition and subtraction.

Essential Knowledge and Skills (Full Curriculum Framework for this SOL)

Determine the missing number in a number sentence (e.g., 3 + __ = 5 or __+ 2 = 5; 5 – __ = 3 or 5 – 2 = __).
Write the related facts for a given addition or subtraction fact (e.g., given 3 + 4 = 7, write 7 – 4 = 3 and 7 – 3 = 4).

Textbook Correlation

	Grade	Lesson(s)
2.9	2	1-6, 1-7, 1-8, 1-10, 1-14

Links to Related SOL

K.6 2.9 3.6 4.3 5.18c 6.3 7.3a

On-Line Games and Practice:

EZ School: Fact Families
Click on the three digits and operation symbols to create the four related number sentences.

IXL: Related Facts
This site offers students the option to choose the related number sentence.

IXL: Fact Families
Type in the missing fact. Click on “explanation” if you don’t understand.

Elementary Software: Fact Triangles
Download the software and use this activity to allow students untimed and timed practice with related facts.

Quia.com: Fact Families
Match the corresponding number sentences to win.

Teacher Reference:

Math Cats: Fact Family FlashCards
Offers strategies for making and using Fact Family cards.

Mathwire.com: Fact Family Mats
Offers strategies and printable mats to allow an organized way for students to explore with dominoes and pictures to record fact families.

Lexington1.net: Fact Families
This is a Powerpoint to explain how facts are related.

Illuminations: Related Facts
This lesson, “Comparing and Connecting Cubes”, allows students to explore the related facts with manipulatives.

Illuminations: Fact Families
This lesson, “Links Away”, progresses from the “Comparing and Connecting Cubes” lesson.

Eduplace: Related Facts
This website discusses conceptual foundation and reasoning behind teaching related facts.

Brain Pop Jr.: Related Facts
This lesson offers ideas and reasons for understanding related facts.

aaamath.com: Inverse Relationship
This site offers examples to explain how this relationship works.

MATH@Freehold Township Schools: Fact Triangles
This site offers ideas of how Fact Triangles can be used.

The School Bell: Fact Families
Ideas for building many families to the same sum.

Quia.com: Fact Families
Interactive Flashcards

Free Worksheets:

Education.com: Fact Families
Fact triangles with spaces to record related facts.

MATH@Freehold Township Schools: Fact Triangles
This worksheet is the Everyday Math PDF of the Fact Triangles.

Donnayoung.org: Fact Triangles
This provides blank triangles for you to fill in to make triangles appropriate for your students.

TLSbooks.com: Fact Families
Each Cat holds a sign with the related numbers in a Fact family. Fill out the number sentences.

Myweblets.com: Fact Families
Many worksheets allowing students practice with addition and subtraction Fact Families.