Number Name (7 & 8 Digit) Chapter Notes | Math Olympiad for Class 5 PDF Download

Introduction

Numbers are used everywhere — in money, dates, population, measurement, and daily life. While we normally write numbers using digits, numbers can also be written in words. Writing numbers in words is called Number Names.

Example:

• 15 → Fifteen
• 243 → Two hundred forty-three

Place Value — The Basis of Number Names

Every digit in a number has a value based on its position.

Indian Number System

• Ones period → Ones, Tens, Hundreds
• Thousands period → Thousands, Ten Thousands
• Lakhs period → Lakhs, Ten Lakhs
• Crores period → Crores, Ten Crores

Example: 1,23,45,678 → One crore twenty-three lakh forty-five thousand six hundred seventy-eight

International Number System

• Ones period → Ones, Tens, Hundreds
• Thousands period → Thousands, Ten Thousands, Hundred Thousands
• Millions period → Millions, Ten Millions, Hundred Millions
• Billions period → Billions, Ten Billions, Hundred Billions

Example: 12,345,678 → Twelve million three hundred forty-five thousand six hundred seventy-eight

7 and 8 Digit Number

• A seven-digit number starts from 1,000,000 (one million) and goes up to 9,999,999 (nine million nine hundred ninety-nine thousand nine hundred ninety-nine).

• An eight-digit number starts from 10,000,000 (ten million) and goes up to 99,999,999 (ninety-nine million nine hundred ninety-nine thousand nine hundred ninety-nine).

These numbers are usually read using the International Number System (millions and billions).

International System of Numeration

In this system, the place values of digits follow a specific sequence: Ones, Tens, Hundreds, Thousands, Ten Thousand, Hundred Thousand, Millions, Ten Million and so on.

Here are some key relationships:

1. 1 hundred = 10 tens
2. 1 thousand = 10 hundreds = 100 tens
3. 1 million = 1,000 thousands

The international place value chart is shown as:

Here, 2 is at the Ones place.
7 is at the Tens place.
9 is at the Hundreds place.
5 is at the Thousands place.
4 is at the Ten Thousand place.
3 is at the Hundred Thousands place.
6 is at the Million place.
8 is at the Ten Million place.

Seven-Digit Numbers (Examples and Names)

1. 10,000,000 → Ten million

2. 20,000,030 → Twenty million thirty

3. 30,000,047 → Thirty million forty-seven

4. 40,000,123 → Forty million one hundred twenty-three

5. 50,009,000 → Fifty million nine thousand

6. 60,049,050 → Sixty million forty-nine thousand fifty

7. 70,200,000 → Seventy million two hundred thousand

8. 80,301,000 → Eighty million three hundred one thousand

9. 90,500,070 → Ninety million five hundred thousand seventy

Eight-Digit Numbers (Examples and Names)

1. 100,000,001 → One hundred million one

2. 200,089,000 → Two hundred million eighty-nine thousand

3. 300,006,000 → Three hundred million six thousand

4. 400,530,000 → Four hundred million five hundred thirty thousand

5. 500,700,000 → Five hundred million seven hundred thousand

6. 600,013,000 → Six hundred million thirteen thousand

7. 700,002,000 → Seven hundred million two thousand

8. 800,000,100 → Eight hundred million one hundred

9. 900,000,058 → Nine hundred million fifty-eight

Writing Number Names: Step-by-Step Method

1. Decide the system: Indian or International.

2. Place commas correctly according to the system.

3. Break the number into groups (crores/lakhs/thousands or millions/thousands).

4. Convert each group to words:

• 1–19 → basic number words (one, two, …, nineteen)
• Tens → twenty, thirty, forty, …, ninety
• Hundreds → digit + “hundred”

5. Combine groups with place names: million, thousand, lakh, crore, etc.

6. Skip zero groups (do not mention them in words).

7. Do not use “and” in whole numbers (used only for decimals).

Use hyphens for numbers from 21–99: twenty-one, thirty-four.

Key Points to Remember

1. Seven-digit numbers always lie between one million and ten million minus one.

2. Eight-digit numbers always lie between ten million and one hundred million minus one.

3. Use place values carefully: millions → hundred thousands → ten thousands → thousands → hundreds → tens → ones.

4. Zeros may change how the name is read. Example:

   • 50,009,000 → Fifty million nine thousand

   • 50,090,000 → Fifty million ninety thousand

Tip for Olympiad: Always notice which system (Indian or International) is given in the question. Write neatly, check commas, and avoid extra words.