Hindu–Arabic numeral system

The Hindu–Arabic Number System

The Hindu–Arabic numeral system is the way most of the world writes numbers today. It is a base ten (decimal) positional numeral system. This means it uses ten basic symbols to show numbers, and where a symbol is placed changes its value.

This system was created between the 1st and 4th centuries by Indian mathematicians. By the 9th century, Arabic mathematicians learned about it and added ways to work with parts of numbers. Important books in Arabic helped spread the system.

It reached Europe during the Middle Ages, especially through a famous book called Liber Abaci by Fibonacci. Before that, it was mostly used in Northern Italy. The system uses ten simple symbols, from zero to nine, to write any number by combining them. These symbols come from old Indian shapes and have developed into different styles used in places like Europe, the Middle East, and the Indian subcontinent.

How It Works

The Hindu–Arabic numeral system uses positional notation in a decimal system. This means the place of a digit shows its value. Later, a decimal marker was added to split whole numbers from parts smaller than one. Today, we often use a decimal point or comma for this. There is also a special sign to show that some digits repeat forever, like in one-third, which is shown with a line above the repeating part.

Even though Arabic writing reads right to left, numbers in this system are read left to right, with the largest digit on the left. This makes it easier to understand when we use different writing directions.

The Symbols

Many different symbols are used to show numbers in the Hindu–Arabic numeral system. Most of these come from old Brahmi numerals.

Over time, these symbols changed and are now used in three main ways:

• The common Western "Arabic numerals" are used with the Latin, Cyrillic, and Greek alphabets. They started from the "West Arabic numerals" made in al-Andalus and the Maghreb.
• The "Arabic–Indic" or "Eastern Arabic numerals" are used with Arabic writing, mainly in what is now Iraq. A version of these is also used in Persian and Urdu.
• The Indian numerals are used with Brahmic family scripts in India and Southeast Asia. Each of India's many scripts has its own number shapes.