Decimal numbering system is a set of mathematical symbols, where they represent numerical values grouped into ten units.
This is the system we normally use to perform numerical counts and mathematical operations, as the symbols that make up this system have groupings made from ten to ten units.
These symbols are called numerals, which are used to form numerals. The digits used are: 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9.
The digits are ordered in different ways, form numbers of any class and order and, depending on the position they occupy, can represent different values.
In this sense, it is possible to say that the decimal numbering system is positional. For example, the number 2 in the numbers 24 and 42 has different values, because in the number 24 it represents the value corresponding to two tens and in the number 42 it corresponds to the value of two units.
The fundamental principle of the decimal system is that ten units of any order form an automatically higher order number. After the orders, the constitutive units of the numbers are grouped into classes, where each class has three orders of special denomination.
Classes and orders of the decimal numbering system
THE first class it's the units, formed by the orders of hundreds, tens and the units themselves. The order of units in this class is represented by the numbers 1 to 9. The order of tens corresponds to the numbers 10, 20, 30, 40, 50, 60, 70, 80 and 90, each of these numbers being ten times the corresponding number in the previous order. The order of hundreds corresponds to the numbers ranging from one to nine hundred, where each one of them is one hundred times the corresponding one in the previous order.
THE second class is the one of thousands, which includes the fourth, fifth and sixth orders, which respectively are the units of thousands, tens of thousands and hundreds of thousands and their names correspond to those of the first class, followed by thousands. E.g.: 2000 (two thousand), 150,000 (one hundred and fifty thousand), etc.
THE third class is the one of millions, which follows the same thousands class standards for the orders. And from that, the classes follow ordinarily: fourth class (billions), fifth class (trillions), sixth class (quadrillions), etc.
See also the meaning of number and numeral.