Twos complement addition Overflow the result exceeds the number ranges condition two numbers has the same sign; checking: the sign is wrong solving increase the data bit-length Examples 0101+0101=1011 101+1010=0111Two’s complement addition Overflow : the result exceeds the number ranges ; condition : two numbers has the same sign; checking: the sign is wrong! solving : increase the data bit-length ! Examples: 0101 + 0101 = 1011 1101 + 1010 = 0111