Computer Data Representation

First note the fundamental terms and concepts.

Number:

• an arithmetical value, expressed by a word, symbol, of figure, representing a particular quantity. (Concise Oxford English Dictionary, 11th ed.)

Zero (0):

• The identity element for addition. A cardinal number indicating the absence of any or all units under consideration. An ordinal number indicating an initial point or origin. (The American Heritage Dictionary of the English Language)
• The concept of zero made the positional numbering system (and by extension mathematics and modern science) possible.

Digit:

• any of the numerals from 0 to 9 especially when forming part of a number. (Concise Oxford English Dictionary, 11th ed.)

Positional Notational System:

• A system of writing numbers in which the position of a digit affects its value. (The American Heritage Dictionary of the English Language)
• A numeration system in which a real number is represented by an ordered set of characters where the value of a character depends on its position (WordNet 2.0)
  

Base:

• The number that is raised to various powers to generate the principal counting units of a number system. (The American Heritage¨ Dictionary of the English Language)
• Determines the number of digits and the value of column positions. The base of the decimal system, for example, is 10.