Inaugurated by IN-SPACe
ISRO Registered Space Tutor
S0-SA1-1216
What is a Number Family for 4?
Grade Level:
Pre-School – Class 2
All domains without exception
Definition
What is it?
A Number Family for a specific number like 4 is a group of related addition and subtraction facts that use the same three numbers. It shows how these numbers are connected through these operations. Think of it like a family where everyone is related!
Simple Example
Quick Example
Imagine you have 4 ladoos. If you eat 1 ladoo, you are left with 3. If you eat 3 ladoos, you are left with 1. This means 1, 3, and 4 are part of a number family because 1 + 3 = 4 and 4 - 1 = 3.
Worked Example
Step-by-Step
Let's find the Number Family for 4 using the numbers 1, 3, and 4.
Step 1: Start with an addition fact. We know that 1 plus 3 equals 4.
1 + 3 = 4
---
Step 2: Now, reverse the order of the first two numbers to get another addition fact.
3 + 1 = 4
---
Step 3: From the first addition fact (1 + 3 = 4), we can form a subtraction fact. Take the total (4) and subtract one of the smaller numbers (1) to get the other smaller number (3).
4 - 1 = 3
---
Step 4: From the first addition fact (1 + 3 = 4), we can form another subtraction fact. Take the total (4) and subtract the other smaller number (3) to get the first smaller number (1).
4 - 3 = 1
---
Answer: The Number Family for 4 (using 1, 3, 4) is: 1 + 3 = 4, 3 + 1 = 4, 4 - 1 = 3, and 4 - 3 = 1.
Why It Matters
Understanding number families helps you solve math problems faster and makes mental math easier. This concept is crucial for building a strong foundation in arithmetic, which you'll use in subjects like algebra and geometry. Engineers and data analysts use these basic relationship understandings every day!
Common Mistakes
MISTAKE: Using numbers that don't add up to the target number for addition facts, e.g., for 4, writing 2 + 3 = 4. | CORRECTION: Always ensure the two smaller numbers add up exactly to the larger number in the family.
MISTAKE: Mixing up the order in subtraction facts, e.g., for 4, writing 1 - 4 = 3. | CORRECTION: In subtraction, the largest number (the sum from addition) must always come first.
MISTAKE: Forgetting to include all four facts (two addition, two subtraction) in the family. | CORRECTION: Remember that a complete number family always has two addition facts and two subtraction facts using the same three numbers.
Practice Questions
Try It Yourself
QUESTION: Write the number family for 5 using the numbers 2, 3, and 5. | ANSWER: 2 + 3 = 5, 3 + 2 = 5, 5 - 2 = 3, 5 - 3 = 2
QUESTION: Which set of facts correctly forms a number family for 6 using the numbers 1, 5, and 6?
A) 1+5=6, 5+1=6, 6-1=5, 6-5=1
B) 1+6=5, 5+1=6, 6-1=5, 6-5=1 | ANSWER: A
QUESTION: You have 7 samosas. If you eat some and are left with 3, what are the three numbers in this family, and what are all the facts? | ANSWER: The three numbers are 3, 4, and 7. The facts are: 3 + 4 = 7, 4 + 3 = 7, 7 - 3 = 4, 7 - 4 = 3.
MCQ
Quick Quiz
Which of these facts belongs to the Number Family for 7 using the numbers 2, 5, and 7?
7 - 2 = 4
2 + 7 = 5
5 + 2 = 7
7 - 5 = 3
The Correct Answer Is:
C
Option C (5 + 2 = 7) is a correct addition fact using the numbers 2, 5, and 7. Options A, B, and D use incorrect results or operations.
Real World Connection
In the Real World
Imagine you are a shopkeeper in a local market. If a customer buys items worth ₹2 and ₹5, you quickly add them to know the total is ₹7. If they pay ₹7 and you need to return change after a ₹2 purchase, you subtract to know you owe ₹5. This is using number families for everyday transactions!
Key Vocabulary
Key Terms
ADDITION: Combining two or more numbers to get a total | SUBTRACTION: Taking one number away from another to find the difference | FACT: A mathematical statement that is true | NUMBER FAMILY: A set of related addition and subtraction facts using the same three numbers
What's Next
What to Learn Next
Great job learning about number families! Next, you can explore number families for larger numbers or learn about fact families for multiplication and division. These build directly on what you've learned here, helping you master more complex math concepts.
