Explain the Excess three codes - BCD to Decimal Conversion

The Excess-3 representation of a number is based on Binary Coded Decimal. It is formed by taking the number in Binary Coded Decimal and adding the binary code for 3 to each of the 4-bit groups. Therefore if we take the number 739, the Binary Coded Decimal representation of it is:  0111 0011 1001. The binary for 3 (in 4 bits) is 0011. To give the Excess-3 for 739 this is added to each of the BCD code groups.

                                    0111 0011 1001
                                +  0011 0011 0011  
                                    1010 0110 1100

Therefore the Excess-3 code for 739 is 1010 0110 1100.