More Questions from Digital Arithmetic Operations and Circuits

BCD addition rule Compute the BCD result of adding 0100 (BCD 4) and 0110 (BCD 6).

Digital Electronics Digital Arithmetic Operations and Circuits Difficulty: Easy
Choose an option
  • A
    00010000BCD
  • B
    00010111BCD
  • C
    00001011BCD
  • D
    00010011BCD
  • E
    00000110BCD

Answer

Correct Answer: 00010000BCD

Explanation

Introduction / Context:Binary-Coded Decimal (BCD) encodes each decimal digit in four bits. Arithmetic in BCD requires digit-wise operations and correction when a nibble exceeds 9. This question tests basic BCD addition and correction logic.

Given Data / Assumptions:

  • BCD digits: 0100 (4) and 0110 (6).
  • Single-digit BCD addition; no incoming carry.
  • We express the final answer as an 8-bit BCD (two nibbles) with the proper correction.

Concept / Approach:Add the two nibbles as binary. If the sum is greater than 1001 (9) or a carry occurs, add 0110 (decimal 6) to correct, producing a carry into the next decimal digit. For 4 + 6, the raw sum is 10 (1010), which requires BCD correction.

Step-by-Step Solution:Raw binary sum: 0100 + 0110 = 1010 (decimal 10).BCD correction: since 1010 > 1001, add 0110 → 1010 + 0110 = 1 0000 (carry into tens place).Final BCD: 0001 0000 (representing decimal 10).

Verification / Alternative check:Decimal check: 4 + 6 = 10. In BCD, 10 is encoded as two digits: 1 and 0 → 0001 0000.

Why Other Options Are Wrong:00010111BCD (17): incorrect; 4 + 6 ≠ 17.00001011BCD (11): incorrect; not the sum of 4 and 6.00010011BCD (13): incorrect result.00000110BCD (6): this is just digit 6, not the sum.

Common Pitfalls:Forgetting the 0110 correction or misplacing the carry into the tens place. Always check whether the nibble exceeds 9 or produced a carry.

Final Answer:00010000BCD

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