# BCD Codes

It is an abbreviation of Binary coded decimal. In this coding each decimal digit is represented by the equivalent 4 bits. So if we are to represent 1110 in binary it is 1011 while in BCD it is 0001 0001. So we can see corresponding binary & BCD equivalent of decimal numbers in the following table:

Decimal            Binary                   BCD

0        0000                       0000

1.         0001                       0001
2.         0010                       0010
3.         0011                       0011
4.         0100                       0100
5.         0101                       0101
6.         0110                       0110
7.         0111                       0111
8.         1000                       1000
9.         1001                       1001
10.         1010                       0001 0000
11.         1011                       0001 0001
12.         1100                       0001 0010
13.         1101                       0001 0011
14.         1110                       0001 0100
15.         1111                       0001 0101

So we see that in BCD we have only 0000-1001 valid combination of 4 bits while 1010-1111 are invalid.

Comparison of Binary and BCD:

1. BCD is lesser efficient than Binary as it takes 8 bits to represent 10 while inbinary it takes only 4 bits
2. While BCD to decimal conversion is simpler
3. BCD arithmetic is complicated