What we know in the West as the Arabic numerals, were not invented by the Arabs.
The numeral system was, in fact, developed in ancient India. Historians have traced it back to the Brahmi numerals which were already in use by the 3rd century BC.
Before the rise of the Arab Empire, the numeral system was already moving west and was mentioned by Severus Sebokht in Syria in 662 AD.
French mathematician Pierre Simon Laplace wrote: "It is India that gave us the ingenuous method of expressing all numbers by the means of ten symbols, each symbol receiving a value of position, as well as an absolute value; a profound and important idea which appears so simple to us now that we ignore its true merit…”
The Arabs adopted the nine numerals from India in the 9th century. It was initially known as the Arabic numerals in the West because it was encountered through the West’s trade with the Arabs and also introduced in Europe through Arabic texts in the tenth century. Europeans therefore contributed it to the Arabs even though the Arabs themselves called it Hindu numerals.
This numeral system is now mostly referred to as the Hindu-Arabic numeral system.