1. Solve the following using two's complement

Question

a. 1101+(-1001)
b. (-1101)+(-1110)
c. 8-9
d. -4-8

Answer 1

a. 1101 + 0111 (two's complement of -1001) = 0100 (4 in decimal)
b. 0011 (two's complement of -1101) + 0010 (two's complement of -1110) = 0101 (positive 5 in decimal)
c. 8 - 9 = 1000 (8 in binary) - 1001 (9 in binary) = 1111 (one in binary, two's complement of -1 in 4-bit representation)
d. -4 - 8 = 1100 (two's complement of -4) + 1000 (two's complement of -8) = 0100 (4 in decimal)