History of Hindu Mathematics: A Source Book v1.c7.s7.13

v1.c7.s7.13

It cannot be said why the strokes were horizontal in Brâhmî and vertical in Kharoṣṭhî and Semitic writings, just as it cannot be said why the writing proceeded from left to right in Brâhmî and from right to left in Kharoṣṭhî and Semitic writings. It appears to us that the Brâhmî and the Kharoṣṭhî (Semitic) numerals have always existed side by side and it cannot be definitely said which of these is the earlier. The difference in writing the symbols 1 to 3, seems to be due to the inherent difference between the two systems of writing. The principles upon which numerical signs are formed in the two systems are quite different.