Question: If there are 2 number system, e.g. Decimal Number System with 10 symbols (0-9) and hexadecimal with 16 Symbols (0-9,A-F), can i conclude that with hexadecimal, i will be able to retain greater accuracy than with the decimal number system due to the higher number of symbols ??

Edit1:
Sorry, i was asking only from the point of view of a computer, it may be for a written calculation or anything

Answer: 
They are two different bases for representing numbers. Neither offers greater accuracy than the other as they are simply different ways of representing a numerical value. Decimal is base 10 whereas hexadecimal is base 16. You could as easily represent any decimal or hex value in octal (base 8) or binary (base 2).

Precision is a better description of what I'm guessing you are referring to. The precision at which a number is stored dictates the accuracy of the representation of that number.

32-bit precision (single precision) is less precise than 64-bit precision (double precision) because there are less bits in which to store the significand.
You cannot say anything about accuracy unless you know what you are trying to represent.

For example, if you are trying to represent things measured in hundredths, e.g., pennies, decimal is more accurate than hex for the same number of digits (2). You cannot represent 0.10 exactly in hex (or binary), but you can in decimal.

See the [General Decimal Arithmetic](http://speleotrove.com/decimal/) web page for more details.