The Indian culture developed the decimal system. The Mohenjo Daro culture of the Indus River valley was using a form of decimal numbering some 5000 years ago. Succeeding cultural changes in this area developed the decimal system into a rigorous numbering system, including the use of zero by the Hindu mathematician some 1500 years ago. The digits we use for the decimal system are the Arabic-Indian digits of 0 through 9. Each number occupies a place value. When 1 is reached, the value goes to 0 and 1 is added to the next place value. This way of counting is old. Indo-European languages are spoken from India to Europe have the same counting system and very similar number words.
Sources;Ask Dr. Math-http:www.forum.swarthmore.edu/dr.math/problems/weiss15564.9.97html
for other information on the decimal system go to your local library in your school or around your town.