
 Positional notation  Wikipedia, the free encyclopedia 
  A positional notation or placevalue notation system is a numeral system in which each position is related to the next by a constant multiplier, a common ratio, called the base (or radix) of that numeral system. 
  Before positional notation became standard, simple additive systems (signvalue notation) were used such as Roman Numerals. 
  For a positional system up to ten the ubiquitous digits 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9 are used, for octal only eight digits up to 7 and for binary only two digits 0 and 1 are needed. 
 en.wikipedia.org /wiki/Positional_notation (1187 words) 
