What is a Number Family of 13?

S0-SA1-1247

Grade Level:

Pre-School – Class 2

All domains without exception

Definition

What is it?

A 'Number Family of 13' includes all the pairs of whole numbers that add up to exactly 13. Think of it like a team where two players' scores always sum up to 13. These pairs help us understand addition and subtraction better.

Simple Example

Quick Example

Imagine you have 13 laddoo. If you eat 5 laddoo, how many are left? The pair (5 and 8) makes 13. So, 8 laddoo are left. This shows that 5 + 8 = 13 and 13 - 5 = 8 are part of the 'Number Family of 13'.

Worked Example

Step-by-Step

Let's find all the pairs that make up the Number Family of 13.

Step 1: Start with 0. What number do you add to 0 to get 13? 0 + 13 = 13. So, (0, 13) is a pair.
---Step 2: Now try 1. What number do you add to 1 to get 13? 1 + 12 = 13. So, (1, 12) is a pair.
---Step 3: Next, 2. What number do you add to 2 to get 13? 2 + 11 = 13. So, (2, 11) is a pair.
---Step 4: Continue this pattern: 3 + 10 = 13, so (3, 10) is a pair.
---Step 5: 4 + 9 = 13, so (4, 9) is a pair.
---Step 6: 5 + 8 = 13, so (5, 8) is a pair.
---Step 7: 6 + 7 = 13, so (6, 7) is a pair.
---Step 8: We stop here because if we go to 7, the pair would be (7, 6), which is just the reverse of (6, 7).

Answer: The number family of 13 includes the pairs: (0, 13), (1, 12), (2, 11), (3, 10), (4, 9), (5, 8), and (6, 7).

Why It Matters

Understanding number families helps you do quick mental math and solve problems faster, which is super useful in daily life. This skill is crucial for careers like banking, accounting, and even game development where you need to calculate scores or resources quickly.

Common Mistakes

MISTAKE: Only finding one pair that adds up to 13. | CORRECTION: Remember a number family includes ALL the pairs of whole numbers that sum up to the target number.

MISTAKE: Including numbers that are not whole numbers (like 5.5 + 7.5). | CORRECTION: For basic number families, we usually focus on whole numbers (0, 1, 2, 3, etc.).

MISTAKE: Forgetting that 0 can be part of a pair (e.g., 0 + 13 = 13). | CORRECTION: Always start from 0 when listing pairs to make sure you don't miss any.

Practice Questions

Try It Yourself

QUESTION: Which number completes the pair for 13: 4 + ___ = 13? | ANSWER: 9

QUESTION: Is the pair (6, 7) part of the Number Family of 13? Why or why not? | ANSWER: Yes, because 6 + 7 = 13.

QUESTION: A cricket team scored 13 runs in an over. If the first two balls got 3 runs and 5 runs, how many runs did the remaining 4 balls score together to reach 13? | ANSWER: 5 runs (3 + 5 = 8, and 13 - 8 = 5)

MCQ

Quick Quiz

Which of these pairs does NOT belong to the Number Family of 13?

(5, 8)

(7, 6)

(4, 9)

(10, 4)

The Correct Answer Is:

Option D, (10, 4), adds up to 14 (10 + 4 = 14), not 13. All other options sum up to 13.

Real World Connection

In the Real World

When you're sharing a packet of 13 biscuits with a friend, understanding number families helps you quickly figure out how many each of you gets if you want to split them unevenly, or how many are left if you eat some. It's like managing your pocket money or calculating change at a local kirana store.

Key Vocabulary

Key Terms

PAIR: Two numbers considered together, like (3, 10) | WHOLE NUMBERS: Counting numbers including zero (0, 1, 2, 3...) | SUM: The result of adding two or more numbers | ADDITION: The process of combining numbers to find their total

What's Next

What to Learn Next

Great job learning about Number Families! Next, you can explore 'Number Families of other numbers' like 10 or 20. This will strengthen your addition and subtraction skills even more and prepare you for trickier math problems!