BCD means Binary coded decimal, its advantage is it can represent decimal numbers in the form of binary value says (0000-0 to 1001-9).

Binary codes are divided into weighted binary code and non weighted binary code,

Excess 3 code is an example of non weighted codes since the position of each bits in excess 3 code does not have weights says like ones, tens, hundred in decimal and 2^0,2^1,2^2, in binary.