3. 2. 7.
There are several types of numbers, and Arabic numerals are the most common. Arabic numerals were not invented by Arabs but by Indians. They should actually be classified as Indian languages, but they were first spread to Arabia and then to the world, so they are called "Arabic numerals".
Numbers are written symbols used to represent numbers. Different numbering systems can use the same numbers.
About 700 years ago, the Arabs conquered the Punjab region. They were surprised to find that the mathematics of the conquered regions was more advanced than theirs. Later, the Arabs introduced this number to Spain. In the 10th century AD, it was spread to other European countries by Pope Gerbert Aurillac.