The Decimal System is a positional numbering system that represents the numbers in base 10, thus using ten different symbols. The decimal word originates in Latin, decem which means precisely ten. The specialists and historians are unanimous in considering that this way of counting in base 10, is due to the ten fingers that we have in the hands. This system uses the symbols 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9. These figures are called Indo-Arabic because they originated in the works initiated by Hindus and Arabs. In the decimal system, each set of ten units forms a new order. For example, ten tens are equivalent to a hundred; ten hundreds equals a thousand, and so on.
The Octal System is a positional numbering system that represents the numbers in base 8, thus using eight different symbols. This system uses the symbols 0, 1, 2, 3, 4, 5, 6 and 7. The octal system is not very well known, having its main applications currently in electronics and computer science. This system was designed to decrease the huge amount of digits that were required to represent a number in binary numbering. However, its use has fallen into disuse with the appearance of the hexadecimal system, which can be even more compact than the octal system.