demarcation of measurement

The real number system is an "Ordered Field" .The 'zero element' has additive and multiplicative meanings. The additive properties automatically demands certain markings

1)Any old civilisation that had a commercial system would need unit of measurements, be it length or weight of silver.Once you had a unit, then the need for sub-units followed, like 'liang' followed by 'qian' and  'feng'; there's always a decimal point. Here you have your zero or abacus position right there. Another example is the difference between owning 10 liangs of silver ,a net debt of 10 liangs of silver and empty pocket but debt free

2)Another example is the christian AD and BC chronological markings which obviously  refer to a zero.

http://www.livescience.com/45510-anno-domini.html

I doubt the 5/6th centuries medevial monks needed hindu math.

The multiplicative properties are also quite intuitive but since its more symbolic, the arabs, said to have invented algebra, probably got the credit of formalising the meaning