Which digital circuit performs addition of numbers?

Which digital circuit performs addition of numbers?

• A. Subtractor
• B. Adder
• C. Multiplier
• D. Divider

Answer: (B)

This question tests recognizing which circuit performs binary addition. An adder is designed to sum two binary numbers, bit by bit, with carries propagating to higher bits. A simple unit called a full-adder adds one bit from each number plus a carry-in, giving a sum bit and a carry-out. Wiring many full-adders in a chain handles multi-bit addition, forming a ripple-carry adder or other faster variants. That’s why this circuit is the one that performs addition. Subtraction, multiplication, and division are handled by subtractors, multipliers, and dividers, respectively. Note that subtraction can also be done by adding a two’s-complement value, which uses an adder, but the device specifically built for addition is the adder.

This question tests recognizing which circuit performs binary addition. An adder is designed to sum two binary numbers, bit by bit, with carries propagating to higher bits. A simple unit called a full-adder adds one bit from each number plus a carry-in, giving a sum bit and a carry-out. Wiring many full-adders in a chain handles multi-bit addition, forming a ripple-carry adder or other faster variants. That’s why this circuit is the one that performs addition.

Subtraction, multiplication, and division are handled by subtractors, multipliers, and dividers, respectively. Note that subtraction can also be done by adding a two’s-complement value, which uses an adder, but the device specifically built for addition is the adder.