Inaugurated by IN-SPACe
ISRO Registered Space Tutor
S0-SA1-1306
What is a Fact Family for 3?
Grade Level:
Pre-School – Class 2
All domains without exception
Definition
What is it?
A 'Fact Family for 3' is a group of four math facts (two addition and two subtraction) that use the same three numbers. These numbers are related to each other, just like members of a real family. For example, if we use the numbers 1, 2, and 3, they form a family of facts.
Simple Example
Quick Example
Imagine you have 3 ladoos. You eat 1 ladoo, and 2 ladoos are left. This shows 3 - 1 = 2. You can also think: if you eat 2 ladoos, 1 ladoo is left (3 - 2 = 1). What if you combine 1 ladoo and 2 ladoos? You get 3 ladoos (1 + 2 = 3). And if you combine 2 ladoos and 1 ladoo? Still 3 ladoos (2 + 1 = 3). All these facts use only the numbers 1, 2, and 3!
Worked Example
Step-by-Step
Let's find the Fact Family for the numbers 2, 3, and 5.
Step 1: Identify the three numbers. They are 2, 3, and 5. Remember, the largest number will usually be the 'total' in addition and the 'starting number' in subtraction.
---
Step 2: Write the first addition fact. Add the two smaller numbers to get the largest number. So, 2 + 3 = 5.
---
Step 3: Write the second addition fact. Just swap the order of the two smaller numbers. So, 3 + 2 = 5.
---
Step 4: Write the first subtraction fact. Start with the largest number and subtract one of the smaller numbers. So, 5 - 2 = 3.
---
Step 5: Write the second subtraction fact. Start with the largest number and subtract the other smaller number. So, 5 - 3 = 2.
---
Answer: The Fact Family for 2, 3, and 5 is:
2 + 3 = 5
3 + 2 = 5
5 - 2 = 3
5 - 3 = 2
Why It Matters
Understanding fact families helps you see how addition and subtraction are connected. This skill is very useful in daily life, like when you're calculating change after buying groceries or splitting costs with friends. It's a foundational concept that helps build strong skills for careers in finance, engineering, or even managing a small business.
Common Mistakes
MISTAKE: Using numbers that are not part of the 'family' in one of the facts. For example, for the family 2, 3, 5, writing 2 + 4 = 6. | CORRECTION: Always use ONLY the three numbers given for that specific fact family. In this case, only 2, 3, and 5.
MISTAKE: Getting confused about which number is the 'total' for addition or the 'starting number' for subtraction. | CORRECTION: The largest number in the family is always the sum in addition (e.g., 2 + 3 = 5) and the number you subtract FROM in subtraction (e.g., 5 - 2 = 3).
MISTAKE: Forgetting one of the four facts (either an addition or a subtraction fact). | CORRECTION: Always remember there are two addition facts and two subtraction facts for most fact families. Make sure you write all four.
Practice Questions
Try It Yourself
QUESTION: Write the Fact Family for the numbers 4, 1, and 5. | ANSWER: 4 + 1 = 5, 1 + 4 = 5, 5 - 4 = 1, 5 - 1 = 4
QUESTION: If a Fact Family has the numbers 6, 2, and 8, what are the four facts? | ANSWER: 6 + 2 = 8, 2 + 6 = 8, 8 - 6 = 2, 8 - 2 = 6
QUESTION: A chaiwala sold 7 cups of chai in the morning and 3 cups in the afternoon. If he started with 10 cups of chai, write the fact family connecting these numbers. | ANSWER: 7 + 3 = 10, 3 + 7 = 10, 10 - 7 = 3, 10 - 3 = 7
MCQ
Quick Quiz
Which of these is NOT part of the Fact Family for 7, 3, and 10?
7 + 3 = 10
10 - 7 = 3
10 - 3 = 7
7 + 4 = 11
The Correct Answer Is:
D
Options A, B, and C all use only the numbers 7, 3, and 10, showing their relationship. Option D uses the number 4 and 11, which are not part of the fact family for 7, 3, and 10.
Real World Connection
In the Real World
Imagine you're tracking your mobile data usage. If you started with 10 GB and used 3 GB, you have 7 GB left. This is 10 - 3 = 7. If you then think about how much you used (3 GB) and how much is left (7 GB), they add up to your total (3 + 7 = 10). This concept helps you understand your data balance, just like a fact family!
Key Vocabulary
Key Terms
FACT FAMILY: A group of four related math facts using three numbers | ADDITION: Combining numbers to find a total | SUBTRACTION: Taking one number away from another to find the difference | SUM: The answer to an addition problem | DIFFERENCE: The answer to a subtraction problem
What's Next
What to Learn Next
Great job learning about Fact Families! Next, you can explore 'Fact Families for Multiplication and Division'. You'll see how multiplication and division are also connected in similar ways, which will make solving bigger problems much easier!
