Signed Integer            

We know that for n-bit number, the range for natural number is from .

For n-bit, we have all together different combination, and we use these different combination to represent numbers, which ranges from .

If we want to include the negative number, naturally, the range will decrease. Half of the combinations are used for positive number and other half is used for negative number.

For n-bit represenatation, the range is from      .

For example, if we consider 8-bit number, then range

             for natural number is from   0   to  255; but
             for signed integer the range is from   -127  to  +127.