South Asian numbering system

The Indian numbering system is used in India as well as in Bangladesh, Nepal, Pakistan, and Sri Lanka. It is based on the Vedic numbering system in which numbers over 9,999 are written in two-digit groups (or a mix of two- and three-digit groups) rather than the three-digit groups used in most other parts of the world. In Pakistan, this system is used in Urdu and other regional language media, but not in English-language media.

The terms lakh or lac (100,000 or 1,00,000 in the Indian system) and crore (10,000,000 or 1,00,00,000 in the Indian system) are used in Indian English to express large numbers. For example, in India 150,000 rupees becomes 1.5 lakh rupees, written as ₹1,50,000 or INR 1,50,000, while 30,000,000 (thirty million) rupees becomes 3 crore rupees, written as ₹3,00,00,000 with commas at the thousand, lakh, and crore levels, and 1,000,000,000 (one billion) rupees (one hundred crore rupees) is written ₹1,00,00,00,000.

The Indian numbering system uses separators differently from the international norm; in such numbers of at least one lakh (one hundred thousand), a comma divides every two rather than every three digits to the left of the last three, thus:

This accords with the Indian numbering system, which has units for thousands, hundreds of thousands, tens of millions, etc.

The table below follows the short scale usage of one billion being one thousand million. In India, Bangladesh and Pakistan, following former British usage, the long scale was used, with one billion equivalent to one million million.

There are various systems of numeration found in various ancient Vedic literatures of India. The following table gives one such system used in the Valmiki Ramayana.

...
Wikipedia