What is the Number 18?

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Grade Level:

Pre-School – Class 2

All domains without exception

Definition

What is it?

The number 18 is a natural number that comes after 17 and before 19. It is an even number, meaning it can be divided into two equal parts without any remainder. We use 18 to count things and represent quantities.

Simple Example

Quick Example

Imagine you have two teams playing cricket. If one team scores 10 runs and the other team scores 8 runs, together they have scored 10 + 8 = 18 runs in total. So, 18 represents the combined score.

Worked Example

Step-by-Step

Let's say your mother bought a dozen (12) bananas from the market. Later, your father brought 6 more bananas. How many bananas do you have in total?

Step 1: Identify the first number of bananas: 12.
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Step 2: Identify the second number of bananas: 6.
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Step 3: To find the total, we add these two numbers together: 12 + 6.
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Step 4: Start from 12 and count 6 more steps: 13, 14, 15, 16, 17, 18.
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Step 5: The total number of bananas is 18.

Answer: You have 18 bananas in total.

Why It Matters

Understanding numbers like 18 is crucial for basic counting, addition, and subtraction, which are building blocks for all of mathematics. It helps in managing daily finances, understanding sports scores, and even in careers like banking, engineering, or becoming a shopkeeper.

Common Mistakes

MISTAKE: Confusing 18 with 81. | CORRECTION: Remember that 18 has 'one' in the tens place and 'eight' in the ones place, while 81 has 'eight' in the tens place and 'one' in the ones place. The order of digits matters a lot!

MISTAKE: Thinking 18 is an odd number. | CORRECTION: An even number can be divided exactly by 2. Since 18 divided by 2 is 9 (with no remainder), 18 is an even number. Odd numbers always have a remainder of 1 when divided by 2.

MISTAKE: Counting incorrectly when adding to reach 18, like saying 9 + 8 = 18. | CORRECTION: Always double-check your addition. You can use your fingers or draw dots to count accurately. 9 + 8 is 17, not 18. 9 + 9 is 18.

Practice Questions

Try It Yourself

QUESTION: If you have 10 ladoos and your friend gives you 8 more, how many ladoos do you have in total? | ANSWER: 18 ladoos

QUESTION: An auto-rickshaw driver completed 5 trips in the morning and 13 trips in the evening. What is the total number of trips he completed? | ANSWER: 18 trips

QUESTION: Your school bus has seats for 25 students. If 7 seats are empty, how many students are currently on the bus? | ANSWER: 18 students

MCQ

Quick Quiz

Which of the following describes the number 18?

It is an odd number.

It comes after 19.

It is an even number.

It is smaller than 10.

The Correct Answer Is:

18 is an even number because it can be divided by 2 to get 9 with no remainder. It comes before 19, not after, and it is larger than 10.

Real World Connection

In the Real World

You see the number 18 everywhere in daily life in India! For example, when you turn 18 years old, you become eligible to vote in elections and get a driving license. Many items in a shop, like a pack of biscuits, might contain 18 pieces, or a bus ticket might cost 18 rupees.

Key Vocabulary

Key Terms

NATURAL NUMBER: A counting number starting from 1 (1, 2, 3...). | EVEN NUMBER: A number that can be divided by 2 without a remainder. | QUANTITY: The amount or number of something. | DIGITS: The symbols used to write numbers (0, 1, 2, 3, 4, 5, 6, 7, 8, 9).

What's Next

What to Learn Next

Great job understanding the number 18! Next, you can explore other numbers and learn about operations like addition and subtraction with larger numbers. This will help you become even better at solving everyday math problems.