Commas, the American way

The idea

In the American system, also called the International system, the digits are grouped uniformly in a 3-3-3… pattern from right to left, giving the places thousands, millions, billions, and so on.

Another way to write the same number

In many countries, such as the USA, numbers are written with a different comma pattern. They also use different names: million and billion.

In the Indian system, ten crore is 10,00,00,000. How do you think it looks in the American system?

• 10,00,00,000 (the same)
• 100,000,000
• 1,00,000,000

Group by threes

The Indian way is shown above each number. Now place the commas the American way.

3-3-3…

In the American system (also called the International system), the digits are grouped uniformly: 3-3-3… from the right. The places are thousands, millions, billions, and so on.

The commas fall in different places, because the Indian system changes to groups of 2 after the first 3 digits.

• Indian | American
• 1,00,000 | 100,000
• 10,00,000 | 1,000,000
• 10,00,00,000 | 100,000,000

Notes

In the American (International) system, the digits are grouped uniformly in a 3-3-3… pattern from right to left, giving thousands, millions, billions, and so on.

Check yourself

Which of these is written the American way?

How many commas are there in 1,000,000,000 (one billion)?

Answer: 3

1,000,000,000 has 4 groups, so 3 commas.

45,00,00,000 is 45 crore in the Indian system. In groups of 3 it is…

• 87,65,432. This has groups of 2: it is the Indian system.
• 8,765,432 — correct. Yes! Groups of 3 from the right: 432, 765, 8.
• 876,54,32. Commas are counted from the right, and every group has 3 digits (except maybe the first).
• 45,000,000. That is only 4.5 crore: one zero is missing. 45 crore has 9 digits.
• 450,000,000 — correct. Yes! The digits are the same, 450000000. Only the commas move.
• 4,500,000,000. That has one zero too many. The digits do not change, only the commas.