What Is BCD Arithmetic ?

• BCD is a binary code of the ten decimal digits. It is not a binary equivalent.
• To perform BCD addition

1. Add the BCD digits as regular binary numbers.
2. If the sum is 9 or less and no carry was generated, it is a valid BCD digit.
3. If the sum produces a carry, the sum is invalid and the number 6 (0110) must be added to the digit.
4. If the sum is greater than nine, the sum is invalid and the number 6 (0110) must be added to the digit.
5. Repeat for each of the BCD digits.