Lesson Plan
Fact Family Foundations Lesson
Students will understand that addition and subtraction are inverse operations and can identify fact families.
This lesson is important because understanding fact families strengthens number sense and builds a strong foundation for future mathematical concepts, making problem-solving easier and more intuitive.
Audience
2nd Grade Class
Time
50 minutes
Approach
Through interactive activities and discussions.
Prep
Review Materials
15 minutes
- Review the Fact Family Foundations Lesson and all accompanying materials.
- Prepare the Our Number Family Slides for presentation.
- Gather any physical manipulatives for the Build-A-Fact-Family Blocks Activity (e.g., actual blocks, counters).
- Print or prepare for digital distribution the The Story of Related Operations Reading.
Step 1
Introduction: What's a Family?
5 minutes
- Begin by asking students what they think of when they hear the word 'family'.
- Connect this idea to 'number families' where numbers are related, just like people in a family.
- Introduce the lesson title: The Number Family Tree.
Step 2
Exploring Number Relationships with Slides
15 minutes
- Present the Our Number Family Slides.
- Guide students through the concept of addition and subtraction as inverse operations using examples.
- Encourage participation by asking questions from the slides and allowing students to share their thinking.
Step 3
Fact Family Discussion
10 minutes
- Facilitate a discussion using the Family Connections Chat prompts.
- Have students share examples of fact families they've discovered or created.
- Emphasize the relationship between the three numbers in a fact family.
Step 4
Building Fact Families Activity
15 minutes
- Distribute materials for the Build-A-Fact-Family Blocks Activity.
- Explain the instructions for creating fact families using blocks or other manipulatives.
- Circulate to provide support and encourage students to explain their reasoning.
Step 5
Cool Down: Reflecting on Related Operations
5 minutes
- Distribute The Story of Related Operations Reading as an exit ticket or cool-down activity.
- Ask students to read the story and reflect on how addition and subtraction are connected.
- Collect their responses to gauge understanding.
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Slide Deck
The Number Family Tree
Exploring the connections between numbers!
Welcome students and introduce the lesson topic in an engaging way.
What's a Number Family?
• A group of three numbers.
• These numbers are related through addition and subtraction.
• They help us understand how numbers work together!
Explain that just like our own families, numbers can be related to each other in special ways. Introduce the idea of a 'number family' or 'fact family'.
Addition Facts in a Family
Let's take the numbers 3, 5, and 8.
• How can we add 3 and 5?
• 3 + 5 = 8
• 5 + 3 = 8
These are two addition facts in our family!
Use an example to show how two smaller numbers add up to a larger number in a fact family. Ask students for other examples.
Subtraction Facts in a Family
Using our family 3, 5, and 8 again:
• If we start with 8, how can we subtract to get 3 or 5?
• 8 - 3 = 5
• 8 - 5 = 3
These are two subtraction facts in our family!
Now, show how the larger number can be used with one of the smaller numbers to perform subtraction. Reinforce the relationship.
Addition & Subtraction: Best Friends!
• Addition and subtraction are inverse operations.
• They are like opposites, but they are connected!
• If you know 3 + 5 = 8, then you also know 8 - 3 = 5!
• One helps you solve the other.
Explicitly state that addition and subtraction are inverse operations. This means they 'undo' each other. Provide a simple analogy if helpful (e.g., zipping and unzipping a coat).
Your Turn! What's the Family for 4, 6, 10?
Can you find all the addition and subtraction facts for this number family?
• __ + __ = __
• __ + __ = __
• __ - __ = __
• __ - __ = __
Engage students with a quick practice problem. Ask them to identify the missing facts or the full fact family for a given set of numbers.
Discussion
Family Connections Chat
Let's chat about our number families! Share your thoughts with the class.
Discussion Prompts:
- What is a number family in your own words? What makes it a "family"?
- Can you give an example of a number family? What are the three numbers in your family?
- How are addition and subtraction like "best friends" in a number family? What does it mean for them to be inverse operations?
- Why is it helpful to know all the facts in a number family? How can it make solving math problems easier?
- Think of a time you used addition to solve a problem. Could you have used subtraction to check your answer? Explain!
Activity
Build-A-Fact-Family Blocks Activity
Objective: To construct and identify fact families using physical manipulatives.
Materials:
- Connecting blocks (e.g., Unifix cubes, LEGOs) or other counters
- Whiteboard or paper for recording
Instructions:
- Work in pairs or small groups. Each group will need a set of connecting blocks or counters.
- Choose three numbers that form a fact family. (Teacher may provide a few starting numbers or allow students to choose).
- Example: You might choose 2, 3, and 5.
- Build the fact family using your blocks.
- For the example (2, 3, 5):
- Make a tower of 2 blocks and another tower of 3 blocks. Connect them to see that 2 + 3 = 5.
- Then, connect 3 blocks and 2 blocks to show 3 + 2 = 5.
- Next, start with a tower of 5 blocks. Remove 2 blocks to show 5 - 2 = 3.
- Finally, start with 5 blocks again and remove 3 blocks to show 5 - 3 = 2.
- For the example (2, 3, 5):
- Record your fact family. On your whiteboard or paper, write down all four facts you created with your blocks:
- Addition Fact 1:
- Addition Fact 2:
- Subtraction Fact 1:
- Subtraction Fact 2:
- Addition Fact 1:
- Share with your classmates! Be ready to explain how your blocks show the relationships in your number family.
Challenge:
Try to build a different fact family with new numbers. What other number families can you find?
Reading
The Story of Related Operations
Once upon a time, in the land of numbers, lived two very important operations: Addition and Subtraction. They were always together, like two sides of the same coin, or two friends who knew each other's secrets.
Addition was a friendly operation. Whenever numbers wanted to grow bigger, they called on Addition. If 3 wanted to join 5, Addition would happily say, "Let's make 8!" And so, 3 + 5 = 8. Addition also loved to show that if 5 joined 3, it would still make 8! (5 + 3 = 8).
Subtraction, on the other hand, was a clever detective. When numbers wanted to know what was left, or what the difference was, Subtraction would step in. But here's the secret: Subtraction always used what Addition had already done to figure things out!
If Subtraction saw that 3 and 5 made 8, it knew that if you started with 8 and took away 3, you would be left with 5 (8 - 3 = 5). And if you started with 8 and took away 5, you would be left with 3 (8 - 5 = 3).
They realized they were always connected. Addition helped numbers grow, and Subtraction helped numbers shrink back to their original parts. They were inverse operations, meaning one could undo what the other did. If you added, you could subtract to get back. If you subtracted, you could add to get back!
And so, Addition and Subtraction worked hand-in-hand, showing all the numbers in the land how beautifully they were related in every family of numbers.
Reflect and Respond:
- What did you learn about Addition and Subtraction from this story?
- How are Addition and Subtraction like "best friends"? What does this story tell you about how they work together?
- Can you think of a number family example (like 3, 5, and 8) and tell your own short story about how Addition and Subtraction work together in that family?