A numeral system is a writing system for expressing numbers. A numeral is a symbol or a group of symbols that express a number. As an example all the next symbols are expressing the value of two : '2', 'א', 'II', '२'.
Why do we need the table below? First of all .. to help us in coin identification.
Please be careful .. as an example if the year "١٤٥٩" is engraved on a coin and you convert it to "1459" this doesn't mean you have a coin from 1459 AD (Anno Domini). There a lot of date systems besides our own. All this about date systems in another article.