Number - Decimal (Hindu–Arabic numeral system)
About
A decimal number 1) is a number coming from the numeral system base 10.
The Hindu–Arabic numeral system, base-10, is the most commonly used system in the world today for most calculations.
The prefix deci- implies base 10.
Each consecutive digit is measured in units one tenth the size of the previous one.
The base-10 (decimal) system was motivated to count with fingers (ie everybody has 10 fingers)