Zero and positional notation: two distinct advances -------------------------------------------------------
The way numbers are represented is a matter of arbitrary choices shaped by history or chance. The decimal system, for example, stems from the fact that we have five fingers on each hand. But imagine that evolution had given us four, or six. Today we would count in base 8, or base 12. There are many ways of combining digits and basic symbols: alphabetic symbols for units, tens and hundreds; Roman numerals; Arabic numerals; the introduction of zero; positional notation… Zero and positional notation are two innovations that are not necessarily linked. The Chinese represent zero with a circle to denote the absence of an element. The rest is written as a sequence of multipliers of powers of 10, each power having its own particular ideogram. Hundreds and units can be placed side by side, omitting the tens, because the power of 10 in question is clear!