(Blue line is for China and the green for India)

The decimal system was perhaps the most revolutionary and greatest scientific achievement in the ancient world in mathematics. The numbers in the decimal system were called Arabic numerals by the Europeans, but surprisingly the Arab scholars called them Hindu numerals. Were they really Arabic or Hindu? In this connection it may be mentioned that the languages Urdu, Persian and Arabic are written from right to left but if you ask any speaker of these languages to write any number e.g. 257 he will write the number from left to right. This shows that these numbers were taken from a language which was written from left to right and not from right to left. It is accepted now that these numbers came from India and they were copied by the Arabs from us. I would like to illustrate the revolutionary significance of the decimal system. As we all know, ancient Rome was a great civilization, but if one would have asked an ancient Roman to write the number one million he would have almost gone crazy because to write one million he would have to write the letter M which stands for millennium (or one thousand) one thousand times. In the Roman numerals there is no single number greater than M, which stands for one thousand. To write 2000 we have to write MM, to write 3000 we have to write MMM, and to write one million one has to write M one thousand times. On the other hand, under our system to express one million we have just to write the number one followed by six zeros. In the Roman numerals there is no zero. Zero was an invention of ancient India and progress was not possible without this invention. One can read about the great contributions of our great mathematicians like Aryabhatta, Brahamgupta, Bhaskar, Varahamihira etc. by using Google. However, I may just give two simple illustrations in this connection. The number 1, 00,000 is called a lakh in the Indian numeral system. 100 lacs is called one crore, 100 crores is called one arab, 100 arabs is called one kharab, 100 kharabs is called one neel, 100 neels is called one padma, 100 padmas is called one shankh, 100 shankh is called one mahashankh, etc. Thus one mahashankh will be the number 1 followed by 19 zeros (for further details you may see V.S. Apte's Sanskrit English Dictionary on the internet by using Google). On the other hand the ancient Romans could not express any number larger than one thousand except by repeating M and the other numerals again and again. Take another illustration. According to the Agni Purana, the Kaliyuga in which we are living consists of 4, 32, 000 years. The preceding Yuga is known as the Dwapar Yuga and is twice as long as the Kaliyuga. Preceding the Dwapar Yuga, is the Treta Yuga which is thrice the duration of the Kaliyuga. The Yuga preceding Treta Yuga is the Satyuga which was said to be four times longer than the Kaliyuga. One Kaliyuga, one Dwapar Yuga, one Treta Yuga and one Satyuga are collectively known as one Chaturyugi (or 43 lacs 20 thousand years). Fifty Six Chaturyugis are known as one Manovantar. Fourteen Manovantars is known as one Kalpa. Twelve Kalpas make one day of Brahma. Brahma is believed to have lived for billions or trillions of years. When our people do the sankalp, which is to be done everyday by orthodox people, they have to mention the exact day, month and year of the Kaliyuga as well as the Chaturyugi, Manovantar and kalpa in which we are living. It is said that we are living today in the 28th Chaturyugi in our present Manovantar, that is to say half the Manovantar of our Kalpa is over, but the remaining Manovantar is yet to be completed. We are living presently in the Vaivasvata Manuvantar. One may or may not believe the above system, but one can only marvel at the flight of imagination of our ancestors who could conceive of billions or trillions of years in history. Aryabhatta in his famous book called the Aryabhatiya wrote about algebra, arithmetic, trigonometry, quadratic equations and the sine table. He calculated the value of Pi at 3.1416, which is close to the actual value which is about 3.14159. Aryabhatta's works were later adopted by the Greeks and then the Arabs.