Our present way of expressing fractions is probably due to the Hindus. Brahmagupta (circa C.E. 630) wrote the (with no bar) to represent “two-thirds” The Arabs introduced the “bar” to separate the two parts of a fraction, but this first attempt did not catch on. Later, due to typesetting constraints, the bar was omitted and, at times, the fraction “two-thirds” was written as 2/3.