i$)$ Represent $(0110{)}_2$ in the following codes.

a$)$ Excess $3$ code

b$)$ Gray code

c$)$ Odd parity Hamming code.

ii$)$ Perform $(21\mathrm{.}5{)}_{10}-(12\mathrm{.}25{)}_{10}$ using $1\text{'}$s complement method.