Помогите решить примеры

$3 \frac{5}{12} - (- 1 \frac{1}{3} ) + ( - 4 \frac{3}{8} ) = 3 \frac{10}{24} + 1 \frac{8}{24} - 4 \frac{9}{24} = \\ \\ = ( 3 + 1 - 4) + \frac{10+8 - 9}{24} = \frac{9}{24} = \frac{3}{8}$

-13.24 + b + 4.9 + 8.24 +(-4.9) = b + (4.9 + (-4.9) ) + (-13.24 + 8.24) =
= b + (4.9 - 4.9) - ( 13.24 - 8.24) = b + 0 - 5 = b - 5
$b = 3 \frac{4}{9} \\ \\ 3 \frac{4}{9} - 5 = - ( 5 - 3 \frac{4}{9} ) = - 1 \frac{5}{9}$