During the Golden Age, which numeral system was spread beyond the Indian subcontinent? Roman
ОООО
Chinese
Greco-Phoenician
Hindu-Arabic

Hindu- Arabic

Explanation:

The word “algorithm” is derived from the name of the scholar al-Khwarizmi. This man was responsible for introducing the Arabic numerals and Hindu-Arabic numeral system beyond the Indian subcontinent.

including the octave, the answer would 8 notes in a major scale with one note being played twice. ex) c major scale includes: c, d, e, f, g, a, b, c

notice that c is played twice

however, if you were to ask me how many different notes are in a major scale- the answer would be 7.