## The Decimal System

Our counting system is based on the number 10 (10 fingers).

The main principle of the decimal system is that 10 is considered as a new unit from which point counting starts again. Ten tens is again a new unit. The multiples of 10 are counted by the same systems as 1 to 9.

1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |

11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 |

' | ' | ' | ' | ' | ' | ' | ' | ' |

' | ' | ' | ' | ' | ' | ' | ' | ' |

' | ' | ' | ' | ' | ' | ' | ' | ' |

91 | 92 | 93 | 94 | 95 | 96 | 97 | 98 | 99 | 100 |

This way of counting is old. Indo-European languages are spoken from India to Europe and have the same counting system and very similar number words. We can conclude that the basic Indo European mother language had the same method of counting - called **decimal counting** (3000 BC).
Remember that no decimal number-system spoken words like twenty three belong to the decimal counting system, 23 belongs to the decimal number notation.

Origins of decimal counting system are hidden - we can see the spread or **diffusion** of our system because people wanted to trade with us.

Other Counting Methods

The Development of Counting Systems and Notations

History of Mathematics Module

Links to other History of Mathematics sites

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These pages are maintained by M.I.Woodcock.