1.3 Of Crores and Crores - NCERT class 7 maths Textbook - Ganita Prakash
1.3 Of Crores and Crores!
“Screen Readable NCERT Class 7 Mathematics Textbook - Ganita Prakash - for Blind and Visually Impaired Students prepared by Professor T K Bansal.”
What if we press the +1000000 button ten times? What number will come up? How many zeroes will it have? What should we call it? The number will be 100 lakhs, which is also called a crore.
1 crore is written as 1,00,00,000 - it is 1 followed by seven zeroes.
The table below shows some numbers according to both the Indian system and the American system (also called the international system) of naming numerals and placing commas. Observe the placement of commas in both systems.
| Indian System | American System | ||
|---|---|---|---|
| 1,000 | One thousand | 1,000 | One thousand |
| 10,000 | Ten thousand | 10,000 | Ten thousand |
| 1,00,000 | One lakh | 100,000 | Hundred thousand |
| 10,00,000 | Ten lakhs | 1,000,000 | One million |
| 1,00,00,000 | One crore | 10,000,000 | Ten million |
| 10,00,00,000 | Ten crores | 100,000,000 | Hundred million |
| 1,00,00,00,000 | One arab or one hundred crores | 1,000,000,000 | One billion |
Notice that in the Indian system, commas are placed to group the digits in a 3-2-2-2... pattern from right to left (thousands, lakhs, crores, etc.). In the American system, the digits are grouped uniformly in a 3-3-3-3… pattern from right to left (thousands, millions, billions, etc.).
The Indian system of naming numbers is also followed in Bhutan, Nepal, SriLanka, Pakistan, Bangladesh, Maldives, Afghanistan, and Myanmar. The words lakh and crore originate from the Sanskrit words laksha and koti. The American system is also used in many countries.
Observe the number of zeroes in 1 lakh and 1 crore.
1 lakh, written in numbers would be 1 followed by 5 zeroes.
1 crore, written in numbers would be 1 followed by 7 zeroes.
A lakh is a hundred times a thousand,
a crore is a hundred times a lakh and
an arab is a hundred times a crore
(i.e., a hundred thousand is 1 lakh, 100 lakhs is 1 crore, and 100 crores is 1 arab).
How many zeros does a thousand lakh have? □ .
How many zeros does a hundred thousand have? □ .
The number 9876501234 can be easily read by placing commas first:
(a) 9,87,65,01,234 → 9 arab 87 crore 65 lakhs 1 thousand and 234 or 987 crore 65 lakh 1 thousand 234 (in the Indian system).
(b) 9,876,501,234 → 9 billion 876 million 501 thousand 234 (in the American system).
Exercise 1.4 - Figure it Out
Question 1.
Read the following numbers in Indian place value notation and write their number names in both the Indian and American systems:
(a) 4050678
(b) 48121620
(c) 20022002
(d) 246813579
(e) 345000543
(f) 1020304050
Question 2.
Write the following numbers in Indian place value notation:
(a) One crore one lakh one thousand ten,
(b) One billion one million one thousand one,
(c) Ten crore twenty lakh thirty thousand forty,
(d) Nine billion eighty million seven hundred thousand six hundred.
Question 3.
Compare and insert the appropriate symbol from the symbols, ‘<’, ‘>’ or ‘=’, in the □:
(a) 30 thousand □ 3 lakhs
(b) 500 lakhs □ 5 million
(c) 800 thousand □ 8 million
(d) 640 crores □ 60 billion
We shall come across even bigger numbers in later grades.