By the end of this chapter you'll be able to…

  • 1Explain that 10 ones make a ten and 10 tens make a hundred
  • 2Identify the hundreds, tens, and ones place in a three-digit number
  • 3State the value of a digit by its place
  • 4Write a number in expanded form
  • 5Build a three-digit number from hundreds, tens, and ones
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Why this chapter matters
House of Hundreds – I builds place value, the backbone of number sense. Children learn that 10 ones make a ten and 10 tens make a hundred, and they read, write, and build three-digit numbers using hundreds, tens, and ones.

Before you start — revise these

A 5-minute refresher here will save you 30 minutes of confusion below.

House of Hundreds – I — Class 3 Mathematics (CBSE)

From the current NCERT Maths Mela Grade 3 book, Chapter 6. Numbers live in a "house" with rooms for hundreds, tens, and ones.


1. Why this chapter matters

Every big number is built from hundreds, tens, and ones. Understanding this place value lets us read, write, and compare numbers, and is the secret behind addition, subtraction, and beyond. This chapter makes place value clear using bundles and a place-value "house".

2. Core ideas

Idea 1 — Ten of one makes one of the next

10 ones = 1 ten, and 10 tens = 1 hundred. We bundle as we grow.

Method 2 — A three-digit number has three places

In 234: the 2 is in the hundreds place (200), the 3 is in the tens place (30), the 4 is in the ones place (4).

Skill 3 — Expanded form shows the value of each digit

234 = 200 + 30 + 4.

3. Worked examples

Example 1: What is the value of 3 in 305?

The 3 is in the hundreds place, so its value is 300. (There are 0 tens.)

Example 2: Build the number with 2 hundreds, 5 tens, 6 ones.

2 hundreds + 5 tens + 6 ones = 256.

Example 3: Write 418 in expanded form.

418 = 400 + 10 + 8.

4. Activity corner

Use bundles of straws (hundreds, tens) and loose straws (ones) to build three numbers, such as 142, 230, and 307. Write:

  • What I built (the bundles and loose straws)
  • The number in figures
  • The maths idea (place value: hundreds, tens, ones)

5. Common mistakes

  • Mistake: Thinking the digit 5 always means five. Fix: Its value depends on its place — in 502 it means 5 hundreds = 500.
  • Mistake: Dropping the zero, writing 305 as 35. Fix: The 0 holds the tens place; 305 has 3 hundreds, 0 tens, 5 ones.
  • Mistake: Mixing up tens and ones. Fix: Ones are on the right, tens next, hundreds on the left.

6. How to write better answers

  1. Identify the place of each digit (hundreds, tens, ones).
  2. Write the value of each digit.
  3. Show expanded form if asked (e.g., 200 + 30 + 4).
  4. Write the number clearly in figures.

7. Practice set

  1. What is the value of 7 in 274?
  2. Build the number: 3 hundreds, 0 tens, 9 ones.
  3. Write 365 in expanded form.
  4. How many tens make one hundred?
  5. Which digit is in the hundreds place in 580?
  6. Write the number for 4 hundreds + 4 tens + 4 ones.

8. Answer key

  1. The 7 is in the tens place, so its value is 70.
  2. 3 hundreds, 0 tens, 9 ones = 309.
  3. 365 = 300 + 60 + 5.
  4. 10 tens make one hundred.
  5. The digit 5 is in the hundreds place (value 500).
  6. 4 hundreds + 4 tens + 4 ones = 444.

9. Quick revision

  • 10 ones = 1 ten; 10 tens = 1 hundred.
  • A three-digit number has hundreds, tens, and ones places.
  • The value of a digit depends on its place (in 234, the 2 means 200).
  • Expanded form: 234 = 200 + 30 + 4.
  • A zero holds a place, so 305 is not the same as 35.

Key formulas & results

Everything you need to memorise, in one card. Screenshot this for revision.

Core idea
10 ones = 1 ten, and 10 tens = 1 hundred.
We bundle as numbers grow.
Math move
A digit's value depends on its place: in 234, 2 = 200, 3 = 30, 4 = 4.
Ones on the right, then tens, then hundreds.
Exam habit
Expanded form shows each digit's value: 234 = 200 + 30 + 4.
A zero holds a place, so 305 is not 35.
⚠️

Common mistakes & fixes

These are the exact errors that cost students marks in board exams. Read them once, save yourself the trouble.

WATCH OUT
Thinking a digit always means its face value
The value depends on the place; in 502 the 5 means 500.
WATCH OUT
Dropping the zero, writing 305 as 35
The 0 holds the tens place; 305 has 3 hundreds, 0 tens, 5 ones.
WATCH OUT
Mixing up tens and ones
Ones are on the right, tens next, hundreds on the left.

Practice problems

Try each one yourself before tapping "Show solution". Active recall > rereading.

Q1EASY· Place value
What is the value of 7 in 274?
Show solution
70 (the 7 is in the tens place).
Q2EASY· Build
Build the number: 3 hundreds, 0 tens, 9 ones.
Show solution
309.
Q3EASY· Expanded
Write 365 in expanded form.
Show solution
300 + 60 + 5.
Q4MEDIUM· Concept
How many tens make one hundred?
Show solution
10 tens make one hundred.
Q5MEDIUM· Place value
Which digit is in the hundreds place in 580, and what is its value?
Show solution
The digit 5, with value 500.
Q6HARD· Build
Write the number for 4 hundreds + 4 tens + 4 ones, and say the value of each 4.
Show solution
444; the first 4 is 400, the second 4 is 40, the third 4 is 4.

5-minute revision

The whole chapter, distilled. Read this the night before the exam.

  • House of Hundreds – I is Chapter 6 of the Class 3 Maths Mela textbook.
  • 10 ones = 1 ten; 10 tens = 1 hundred.
  • A three-digit number has hundreds, tens, and ones places.
  • A digit's value depends on its place (in 234, the 2 means 200).
  • Expanded form: 234 = 200 + 30 + 4.
  • A zero holds a place, so 305 is not the same as 35.

CBSE marks blueprint

Where the marks come from in this chapter — so you can plan your prep.

Typical chapter weightage: 3-4 marks in school tests, oral checks, notebooks, and activities

Question typeMarks eachTypical countWhat it tests
Very Short12-3Value of a digit, building a number, or expanded form
Short Answer21-2Place-value reasoning and bundling
Activity / Project30-1Building numbers with bundles and explaining place value
Prep strategy
  • Practise saying the place and value of each digit
  • Write numbers in expanded form
  • Build numbers using bundles of ten and a hundred
  • Watch the zero as a place holder

Where this shows up in the real world

This chapter isn't just an exam topic — it lives in the world around you.

Reading larger numbers

Place value lets us read prices, page numbers, and house numbers correctly.

Adding and subtracting

Lining up hundreds, tens, and ones is the basis of column arithmetic.

Money and counting

Bundles of hundreds and tens mirror how we count notes and coins.

Exam strategy

Battle-tested tips from teachers and toppers for this chapter.

  1. Underline the command word: value, build, or expanded form
  2. State the place before the value of a digit
  3. Keep the zero as a place holder
  4. Write expanded form as hundreds + tens + ones

Going beyond the textbook

For olympiad aspirants and curious learners — topics that build on this chapter.

  • Make the largest three-digit number using the digits 4, 0, and 7, and write its expanded form.
  • How many tens are there in all in the number 250?

Where else this chapter is tested

CBSE board isn't the only one — other exams test this chapter too.

CBSE Class 3 School AssessmentHigh
Class 3 Foundation / Olympiad PracticeMedium
Notebook and Activity EvaluationHigh

Questions students ask

The real ones — pulled from the Q&A community and tutor sessions.

Place value means the value of a digit depends on its position. In 234, the 2 is in the hundreds place and means 200.

The zero holds the tens place, showing there are 0 tens. Without it, 305 would wrongly become 35.
Verified by the tuition.in editorial team
Last reviewed on 31 May 2026. Written and reviewed by subject-matter experts — read about our process.
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