Question 1: They developed a decimal system with a numeral for zero.
An important development in mathematics during this period was the decimal system notation. The powers of ten with null coefficients were used in order to indicate "zero."
Question 2: Chandragupta II
Chandragupta II was one of the most powerful emperor of the Gupta Empire. Under his rule (c. 380-c. 415) the Gupta Empire reached its greatest size. He was a great supporter of the arts and his rule is often referred to as the “Golden Age” of India.
Question 3: Chess
Chess is believed to have originated in India during the Gupta Empire in the 6th century. Afterwards, it spread through the Silk Road.