20. Assume numbers are represented in 8-bit twos complement representation. Convert to binary and show the calculation. Also indicate if the operation results in a carry bit, and/or if it is a case of overflow. a. 6+13 b. -6+ 13 c. 6-13 d. 6-13 21. Find the following differences using twos complement arithmetic. Also indicate if the operation results in a carry bit, and/or if it is a case of overflow. a. 111000 b. 11001100 c. 111100001111 d. 11000011 - 11101000 - 110011 - 101110 - 110011110011 22. Perform the following operations of unsigned integers in Binary: 1001 (9) 1101/10110111 x 1011 (11)