In BCD (Binary-Coded Decimal) arithmetic, operations are performed on base-10 digit representations (0000–1001 for 0–9) with decimal correction when needed. Evaluate this statement.

Introduction / Context:
BCD is used when exact decimal digit handling matters, such as financial computations or display drivers. Each decimal digit is encoded separately into a 4-bit nibble, enabling precise decimal operations and easy conversion to human-readable form.

Given Data / Assumptions:

• Valid BCD digit codes: 0000–1001 (0–9).
• Invalid patterns 1010–1111 may appear transiently and require correction.
• Addition may require adding 0110 (6) to compensate when a nibble exceeds 9 or a carry occurs.

Concept / Approach:
BCD arithmetic proceeds digit-by-digit. After binary addition of two BCD digits plus carry-in, if the partial nibble result is > 1001 or a carry is generated, add 0110 to that nibble and propagate the carry to the next decade, ensuring decimal correctness.

Step-by-Step Solution:
1) Add lower BCD nibbles with binary adder.2) If result > 9 or carry = 1, add 6 (0110) to correct.3) Propagate carry to the next higher BCD digit.4) Repeat for all digits to complete decimal-correct addition.

Verification / Alternative check:
Example: 9 (1001) + 7 (0111) = 10000 (16). Lower nibble 0000 with carry; add 0110 to correct yields proper BCD result of 16 across two digits.

Why Other Options Are Wrong:
“Incorrect” contradicts BCD practice. “Pure base-2” ignores decimal correction. “All 4-bit patterns valid” is false—1010–1111 are invalid BCD digits.

Common Pitfalls:
Forgetting to add 6 on overflow; assuming binary sum alone suffices for decimal presentation.

Final Answer:
Correct