Capabilities of a 4-bit adder IC: Which operation(s) can a standard 4-bit binary adder perform without additional gating logic?

Introduction / Context:A 4-bit adder IC (e.g., 74HC283/74LS283) provides parallel addition of two 4-bit operands with Cin/Cout for cascading. Other arithmetic/logic functions often require external gating or dedicated ALU chips.

Given Data / Assumptions:

• Device: standard 4-bit adder, not a full ALU.
• Inputs: A[3:0], B[3:0], Cin; Outputs: S[3:0], Cout.

Concept / Approach:Plain addition is native. Subtraction can be realized in a system by inverting B and setting Cin=1 (two's-complement technique), but that requires extra inversion hardware; the bare adder alone does not implement subtraction or AND by itself. Therefore, the only operation directly supported by the chip without external gating is addition.

Step-by-Step Solution:

Verification / Alternative check:Datasheets name the part a “binary adder”; subtraction examples always show complemented inputs and Cin=1 using extra gates.

Why Other Options Are Wrong:

Common Pitfalls:Assuming ALU capabilities from an adder part number.

Final Answer:addition