Perform the following computation in binary using the floating$-$point addition and multiplication. Assume $4$ bits precision. Show your work. $(9$ points$)$

a$){13\mathrm{.}25}_{10}+{15\mathrm{.}5}_{10}$

b$){10\mathrm{.}5}_{10}-{6\mathrm{.}4375}_{10}$

c$){3\mathrm{.}75}_{10}{2\mathrm{.}25}_{10}$