Q. How can one decide this decimal position?

Decimal position can be signified by a position between flip-flops (storage cells in computer). However how can one decide this decimal position? Well to simplify representation aspect two methods were proposed: (1) Fixed point representation where binary decimal position is presumed either at beginning or at end of a number and (2) Floating point representation where a second register is used to keep value of exponent which determines position of binary or decimal point in number. However before determining these two representations let's first discuss a term 'complement' of a number. These complements can be used to signify negative numbers in digital computers.