Compute binary addition: 1001 plus 0011.

Compute binary addition: 1001 plus 0011.

• A. 1000
• B. 1100
• C. 1010
• D. 1110

Answer: (B)

Binary addition uses base-2 rules: 0+0 is 0, 0+1 is 1, and 1+1 is 10 (write 0 and carry 1 to the next bit). Align the numbers and add from right to left. The rightmost column: 1 plus 1 gives 0 with a carry of 1. Next column: 0 plus 1 plus the carried 1 gives 0 with a carry of 1. Next column: 0 plus 0 plus the carried 1 gives 1 with no carry. Final column: 1 plus 0 gives 1. Reading from left to right, the sum is 1100. This carry pattern matches the actual result; the other options would require different carries in those middle bits and don’t fit the calculation.

Binary addition uses base-2 rules: 0+0 is 0, 0+1 is 1, and 1+1 is 10 (write 0 and carry 1 to the next bit). Align the numbers and add from right to left. The rightmost column: 1 plus 1 gives 0 with a carry of 1. Next column: 0 plus 1 plus the carried 1 gives 0 with a carry of 1. Next column: 0 plus 0 plus the carried 1 gives 1 with no carry. Final column: 1 plus 0 gives 1. Reading from left to right, the sum is 1100. This carry pattern matches the actual result; the other options would require different carries in those middle bits and don’t fit the calculation.