What is a Three-Digit Number?

S0-SA1-0020

Grade Level:

Class 2

Maths

Definition

What is it?

A three-digit number is any whole number that has exactly three digits. These numbers start from 100 and go up to 999. Each digit in a three-digit number holds a specific place value: hundreds, tens, and ones.

Simple Example

Quick Example

Imagine you are checking the score of an IPL cricket match. If your favourite team scores 185 runs, '185' is a three-digit number. It has three digits: 1, 8, and 5.

Worked Example

Step-by-Step

Let's identify the three-digit numbers from a list: 9, 105, 78, 999, 1000.

Step 1: Look at the number 9. It has only one digit.
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Step 2: Look at the number 105. It has three digits (1, 0, 5).
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Step 3: Look at the number 78. It has two digits.
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Step 4: Look at the number 999. It has three digits (9, 9, 9).
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Step 5: Look at the number 1000. It has four digits (1, 0, 0, 0).
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Answer: The three-digit numbers in the list are 105 and 999.

Why It Matters

Understanding three-digit numbers is fundamental for basic arithmetic and building a strong math foundation. It's crucial for managing money, like calculating prices at a grocery store, or understanding distances on a map. People working in finance, engineering, or even managing a small business use these concepts daily.

Common Mistakes

MISTAKE: Thinking 99 is a three-digit number | CORRECTION: 99 has only two digits. The smallest three-digit number is 100.

MISTAKE: Confusing 1000 as a three-digit number | CORRECTION: 1000 has four digits (1, 0, 0, 0). Three-digit numbers go up to 999.

MISTAKE: Ignoring the zero in numbers like 205 | CORRECTION: The zero in 205 is a digit and holds the tens place value. So 205 is indeed a three-digit number.

Practice Questions

Try It Yourself

QUESTION: Is 45 a three-digit number? | ANSWER: No

QUESTION: What is the largest three-digit number? | ANSWER: 999

QUESTION: How many three-digit numbers are there in total? (Hint: Think about 999 - 99) | ANSWER: 900

MCQ

Quick Quiz

Which of the following is NOT a three-digit number?

345

900

101

The Correct Answer Is:

99 has only two digits (9 and 9). All other options (345, 900, 101) have exactly three digits.

Real World Connection

In the Real World

When you buy groceries, the total bill often runs into three-digit numbers, like Rs 250 for vegetables or Rs 780 for monthly supplies. Also, when checking the mileage of a car or bike, it often shows three-digit numbers on the odometer, like 150 km covered in a trip.

Key Vocabulary

Key Terms

DIGIT: A single symbol used to write numbers (0, 1, 2, 3, 4, 5, 6, 7, 8, 9) | PLACE VALUE: The value of a digit based on its position in a number | HUNDREDS PLACE: The third position from the right in a number | TENS PLACE: The second position from the right in a number | ONES PLACE: The first position from the right in a number

What's Next

What to Learn Next

Now that you understand three-digit numbers, you're ready to explore four-digit numbers and beyond. This will help you understand even larger numbers used in daily life, like population counts or large financial transactions.