The article says that at Rs.45 to a dollar, India's GDP would have been $900 million and that it is become a trillion because of the appreciation of the rupee by about 10%.
But 1000 millions make one billion and not one trillion. Trillion means a million millions. In other words, trillion is 1 followed by 12 zeroes (1,000,000,000,000)while billion is 1 followed by 9 zeros.(1,000,000,000)
