Binary Coded Decimal (BCD) encodes decimal digits using which form?

Binary Coded Decimal (BCD) encodes decimal digits using which form?

• A. ASCII codes
• B. 8-bit bytes
• C. 16-bit words
• D. 4-bit binary patterns

Answer: (D)

Binary Coded Decimal encodes each decimal digit with a 4-bit pattern. A digit 0–9 can be represented in four bits (0000 to 1001), so BCD uses one 4-bit group per digit, often packing two digits into one byte (one in the upper nibble and one in the lower nibble). This keeps calculations and display logic aligned with decimal digits, rather than using full character codes or larger word sizes. ASCII maps digits to 8-bit characters, not to compact 4-bit patterns, and using a whole byte or a 16-bit word is about data size, not the encoding method itself.

Binary Coded Decimal encodes each decimal digit with a 4-bit pattern. A digit 0–9 can be represented in four bits (0000 to 1001), so BCD uses one 4-bit group per digit, often packing two digits into one byte (one in the upper nibble and one in the lower nibble). This keeps calculations and display logic aligned with decimal digits, rather than using full character codes or larger word sizes. ASCII maps digits to 8-bit characters, not to compact 4-bit patterns, and using a whole byte or a 16-bit word is about data size, not the encoding method itself.