Number System

Mainly there are two number systems. Positional number system and non-positional number system. The system we use in our day to day life for counting and calculating is positional number system. The best example is decimal number system. In positional number system the value of each digit in the entire number is determined by the symbol as well as the place(position) the digit occupies in the number.
For example in number 572
2 is in oneth position, 7 is in tenth position and 5 is in hundredth position
ie 572 = 5 x 100 + 7 x 10 + 2 x 1
All types of calculation is based on the position.
In non-positional system there is no significance for position of the digits. This system cannot be used for calculation. One example is Roman numerals which goes like I, II, III, IV, V, VI, .....