- If it's a positive number, simply write down the six bit binary number that represents the denary number
- If it's negative, write down the binary representation, and then change all the zeros to ones, and ones to zeros.
So the answers to (a) and (c) are:
(c) 7 is 000111 in binary. So -7 is 111000 in ones complement
I'll leave you to do the other two.