$(89)$

$($a$)$ Convert $A=1\mathrm{.}25$ so and $B=-3\mathrm{.}625$ se to $2\text{'}$s complement numbers with $4-$bits for integer and $3-$bits for fraction. $(4\%)$

$($b$)$ Calculate $A+B.$ Show your results in a binary number. Explain that your result is correct. $(4\%)$