Interesting Math History

Question :
What led to 'Ten' as the base of the generally used number system ?

Answer :
Perhaps the use of the fingers on both hands in counting led to the use of ten as the base of the number system. Latter on symbols were used to represent numbers.
The numeral system which has base 10 is called Decimal Numeral system.
It has various symbols called digits with distinct vales (0, 1, 2, 3, 4, 5, 6, 7, 8, 9).

The is a positional numeral system which has positions for units, tens, hundreds, thousands, etc.