Nicholas Bodley recently said:

> ...that is, number with many digits...
> I once heard /read that in India, it was the custom to separate
> the digits of large numbers into groups of four, instead of
> three, as we "Eurocentric" people do now.

Well I've seen it with a group of three followed by groups of two.

It's based on the names of the larger numbers

English
1,000 thousand
1,000,000 million
1,000,000,000 billion (American)

Sanskrit
1,000 sahasram (thousand)
1,00,000 laksam (lakh)
1,00,00,000 kotih (crore)

It just makes it easier to write them as you say them.

Tim

--
Tim Partridge. Any opinions expressed are mine only and not those of my employer