The modern number system was invented by the Indians. Despite that, the numeral system used today is called Arabic or Hindu-Arabic because the Arabs were the ones to bring it to Europe.
The number system invented by the Indians was a combination of 10 digits. It is a place-value system, which means a zero is necessary for arithmetic operations. The Italian mathematician Fibonacci, also known as Leonardo Pisano Bigollo, introduced the Arabic numbers to Europe in the 12th century. Before the arrival of the number system, Roman figures were used instead. The Romans used an additive and subtractive system, which was largely a legacy of the ancient Etruscan period.