find the sum and the product of each of these pairs of numbers. express your answers as a binary expansion. a) (100 0111)2, (111 0111)2 b) (1110 1111)2, (1011 1101)2 c) (10 1010 1010)2, (1 1111 0000)2 d) (10 0000 0001)2, (11 1111 1111)2