What is The Number 400?

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Grade Level:

Pre-School – Class 2

All domains without exception

Definition

What is it?

The number 400 is a natural number that comes after 399 and before 401. It is a three-digit number, specifically a 'hundreds' number, representing four groups of one hundred.

Simple Example

Quick Example

Imagine you are collecting cricket cards. If you have 399 cards and your friend gives you one more, you will now have 400 cricket cards. That's a lot of cards!

Worked Example

Step-by-Step

Let's say a shopkeeper sold 250 packets of biscuits in the morning and 150 packets in the evening. How many packets did he sell in total? --- Step 1: Identify the numbers to add: 250 and 150. --- Step 2: Add the ones digits: 0 + 0 = 0. --- Step 3: Add the tens digits: 5 + 5 = 10. Write down 0 and carry over 1 to the hundreds place. --- Step 4: Add the hundreds digits, including the carried over 1: 2 + 1 + 1 (carried over) = 4. --- Step 5: Combine the results. So, 250 + 150 = 400. --- Answer: The shopkeeper sold 400 packets of biscuits in total.

Why It Matters

Understanding numbers like 400 is fundamental for daily life, from counting money to understanding distances. It's crucial for subjects like mathematics, science, and even commerce. Careers like banking, engineering, and data analysis rely heavily on number sense.

Common Mistakes

MISTAKE: Confusing 400 with 40 or 4000 | CORRECTION: Always check the number of digits and the place value of each digit. 400 has three digits, with 4 in the hundreds place.

MISTAKE: Incorrectly writing 400 as 'four zero zero' instead of 'four hundred' | CORRECTION: When speaking about the number, use its proper name, 'four hundred'. When writing, use the numeral '400'.

MISTAKE: Thinking 400 is a small number when compared to 40 | CORRECTION: 400 is ten times larger than 40. Always compare numbers by their actual value, not just how they look.

Practice Questions

Try It Yourself

QUESTION: If you have 200 rupees and your uncle gives you another 200 rupees, how much money do you have in total? | ANSWER: 400 rupees

QUESTION: A school has 350 students. If 50 new students join, what is the total number of students now? | ANSWER: 400 students

QUESTION: An auto-rickshaw driver covered 175 km on Monday and 225 km on Tuesday. What is the total distance he covered over these two days? Show your working. | ANSWER: 175 + 225 = 400 km

MCQ

Quick Quiz

Which of these represents the number 400?

399 + 1

200 + 100

40 + 0

4000 - 1

The Correct Answer Is:

Option A, 399 + 1, correctly adds up to 400. Option B gives 300, Option C gives 40, and Option D gives 3999.

Real World Connection

In the Real World

You might see the number 400 when looking at the storage capacity of a mobile phone (e.g., 400 GB), the maximum marks in a school exam, or even the number of runs a cricket team needs to score in a long match.

Key Vocabulary

Key Terms

NATURAL NUMBER: A whole number greater than 0, used for counting. | PLACE VALUE: The value of a digit based on its position in a number. | HUNDREDS: The place value representing groups of one hundred. | SUM: The result of adding two or more numbers.

What's Next

What to Learn Next

Great job understanding 400! Next, you can explore larger numbers like 1000 or 5000, and how they are used in everyday situations. This will help you become even better at counting and calculating!