Addition and Subtraction Fact Families By: Sandra Harris

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Addition and Subtraction Fact Families By: Sandra Harris

Fact Families

Launch Begin the lesson by talking about different families in the classroom. Ask students about their families and how many people are part of their immediate and extended family. Ask students to show you, how they would write an addition problem that says, “Jenny has 2 parents and 5 children in her house. How many people does she have in her house altogether?” Then, have them write the subtractions problems that are possible from the same problem.

Investigate Pass out 18 math manipulatives to each student. I will use Teddy Bear counters. Explain to students that math facts live in families of 3. There is one big number and 2 baby numbers in every family. Furthermore, all fact families live in triangle houses. Draw a triangle on a piece of construction paper. Put the number 8 at the top point. Ask students to count out 8 of their manipulatives. Then ask students to divide their group of 8 into a group of 3 and a group of 5. Now write a 3 and a 5 in the bottom two points of the triangle. Show students how they can use this triangle fact house to help them add and subtract. Point as you state 3 plus 5 equals 8. Point as you state 5 plus 3 equals 8. Point as you state 8 minus 5 equals 3. Point as you state 8 minus 3 equals 5. Now have students break into groups of two and use their own manipulatives. Have them use the number of people in their household. Use those two numbers as the smaller numbers to get the bigger number. Have the groups discuss what possible problems would come from their fact family. Repeat the entire process with different numbers between 3 and 18 until students seem to understand the concept.

Discuss Look at the different problems of addition and subtraction that can be created from their fact families. What do you notice? Do you think that order could be changed in any directions and the answers would be the same? Could we flip the problem and not change the answer? Can fact families help us understand addition and subtraction better? If so, how? Can we use this knowledge in everyday life?

Practice Tell students that they will now choose their own number between 3 and 18. Have students count out the correct number of manipulatives. Pass out construction paper houses. Instruct students to write their number at the top of their house. Have students divide their manipulatives into two groups. Students count the manipulatives in each group and record the numbers in top corners of their house roof . Refer students to the teacher model. In the center of each house, students write the two addition and two subtraction sentences they can make with their fact family. If students get done, they may decorate their fact family house or make another fact family house. All of the fact family houses will be displayed on a class bulletin board titled Triangle Town. Allow students time to complete their houses.

Practice Read the book One Nation: America by the Numbers By: Devin Scillian to your students. Then give them a worksheet, American Fact Families to complete. Students will write a number sentence to represent an addition or subtraction problem that relates to the book. Then students will write the missing number sentences in that fact family. Ask students to tell a story to match the missing number sentences they wrote. The stories should relate to the original number sentence. For instance, for the number sentence = 3, a student might say “First the Nina landed in the New World. Then the Pinta and the Santa Maria landed. How many ships were there all together?”

Internet Game Practice

Evaluate Students' fact family houses will be graded on their ability to create the correct addition and subtraction facts with the number they chose. I will ask the students to look at another students house and they will need to be able to state the two addition and subtraction facts that go with that house. Students should be able to answer all four questions.

Self- Evaluation Have students pick small groups of two or three. In these groups have the children discuss how they each did their problems. Allow the students time to discuss their fact family. Have the child fill out a self- grade sheet asking questions about their own performance.

End Tell me what we have learned about today.
What is something we learned about addition and subtraction problems? What the best part of this lesson? I'm going to send you an extra fact families house home for extra practice if you want to do it. I want you to pick a number larger than 18. Use items at home as your manipulatives and find the possible problems.

Modifications Gearing Up: If this lesson was too easy, I could increase the value of the large number I allow the students to pick from. I used 3 to 18 and I could increase the numbers depending on the what the group is capable of. Gearing Down: If this lesson was too challenging, I could decrease the gap of numbers allowed to chose from. Also, we could do more examples together before completing our own house.

References

Teacher’s page of Objectives
Process Standards Problem Solving: Students should be able to determine that addition and subtraction problems will be the same if flipped. Reasoning and Proof: Students should be able to solve their problems to prove that each fact family consists of three numbers. Communication: Students should be able to tell what the subtraction and addition problems of a fact family would be. Connections: Students should be able to connect the number problem to a word problem that tells a story. Representations: Students should be able to create a house that has four problems written on it. NCTM Numbers and Operations Content Objective (GLE) Math: Numbers and Operations 3: C- apply and describe the strategy used to solve addition or subtraction problems. Students should be able to identify related addition and subtraction facts. Students will create number sentences that are fact families. Background Knowledge Needed Students should be able to perform basic addition and subtraction