Decimal numbers are defined as those characters that express both rational and irrational numbers, in other words, these are non-integer numerical expressions and which has within its composition a decimal portion, and another integer, which are separated from each other. by a comma, understood as a way of expressing fractions that arise thanks to a quotient that is not exact.
Within the group of decimal numbers are encompassed, both rational numbers which can be expressed by using fractions of a pair of whole numbers, as well as contain irrational numbers, which are used when it is not possible to represent in the form of fraction of two whole numbers. It is important to note that in the set of rational numbers there is another subdivision and they are the periodic and exact decimal numbers, the former being those that are composed of a periodic part that can present indefinitely, for example 1.6666. While the exact ones only have a finite decimal.
The composition of the decimal numbers is as follows, on the one hand they are made up of an integer element and the other decimal, which are separated one from the other by symbols such as comma or period, in addition to that they are also characterized by the position the denominator occupies. On the one hand, the decimal numbers are located just after the symbol that separates them from the integers, while the hundredths are located after the decimal, that is, two places after the symbol.
In basic arithmetic operations such as addition and subtraction, it is necessary that the decimal numbers are located vertically, that is, that the figures that make up said operation are located one below the other, in such a way that the symbol matches in the same position as the other figures, regardless of whether the entire portion of it has more characters than another, all this is done in order to make these operations much easier. On the other hand, in the case of multiplication, the procedure is totally different, since the operation is carried out without taking into account the symbol, then the comma must be placed, after adding the totalof the decimal elements that made up the operation, for example if in the multiplication one of the factors had 3 decimal places and the other had 2, this means that at the end of the operation the result must have 5 decimal places.
