1. 11011101 (2) = 335 (8);1011110111 (2) = 759 (10);2. 12371 (8) = 1010011111001 (2);716 (8) = 462 (10);125 (8) = 85 (10);3. AB9 (16) = 101010111001 (2);9BD (16) = 100110111101 (2);179F (16) = 13637 (8);AFD3 (16) = 127723 (8);BCD (16) = 3021 (10);1A2B3C (16) = 1715004 (10);4. 1011 + 101 = 10000;1011 - 101 = 0110;1011 * 101 = 110111;1011 / 101 = 10;11101 + 11 = 100000;11101 - 11 = 11010;11101 * 11 = 1010111;11101 / 11 =1001;1111 + 1011 = 11010;1111 - 1011 = 100;1111 * 1011 = 10100101;1111 / 1011 = 1.