Lakhs and crores are units of the Indian numbering system commonly used throughout the Indian subcontinent. Billions, on the other hand, are used internationally and are equivalent to "thousands of millions" and are grouped accordingly when represented numerically. For example, 2 billion would be represented as 2,000,000,000. It can also be abbreviated to 2B.
1 billion (or 1000 million) is equivalent to 100 crores. If converted to lakhs, 1 billion would be 10,000 lakhs.