Evaluate the following expressions, in which each operand is an 8 bit 2s complement number, using the standard binary addition algorithm (evaluate the subtraction in part (a) by negating then adding). As well as showing each result in 8 bit 2s complement, also convert and express each as a signed decimal number. Note that whenever there is signed overflow your answer will not be correct. For which expression(s) does this occur?

(a) 11111111 - 01111111 (b) 10111010 + 11000010 (c) 10111110 + 11010111