please answer 4,5, and 6. i will like the oost. thank you for ur time

Negative (I)=10kI,k is the number of digits a) How many positive integers Can be represented? b) How many negative integers Can be represented? 3) Evaluate the Following expressions, Where A is 111111010 and B is 000000011 , using twos complement solve the following, a) A+B b) AB 4) How can the decimal number 123.433 be represented as a sign, mantissa and exponent? 5) How would the following string of characters be represented using run-length encoding? What is the compression ratio? 6) How many integers can get represented by a 7 bit twos complement representation ? Give your answer in decimal and then convert it to octal. 7) Given the following Huffman encoding table, decipher the bit string that follow. 0110101010100101011111000