Answer
To serve as a Place Holder.
Work Step by Step
Consider a Number \[400806\]in Hindu Arabic System.
It’s Expanded form is \[4\,\times \,{{10}^{5}}\,+\,8\,\times \,{{10}^{2}}\,+\,6\times 1\].
Now, suppose if there is no zero, we have to leave blank spaces for the missing powers of \[10\].
The number will be written as $4\,\,8\,6$ which cannot be considered as the perfect representation of above expansion. So, Symbol for Zero was required to serve as a placeholder.
To represent nothingness, the symbol for zero was needed.
