Помогите пожалуйста решить примеры

А)
$(800-981 * frac{5}{8} ) * frac{1}{5} = 800 * frac{1}{5} - 981 * frac{5}{8} * frac{1}{5} = = frac{800*1}{1*5} - frac{981*5*1}{1*8*5} = frac{800}{5} - frac{981}{8} = =160- 122 frac{5}{8} =37 frac{3}{8}$

$800-981 * frac{5}{8} * frac{1}{5} = 800- frac{981}{8} = 800-122 frac{5}{8} =677 frac{3}{8}$

б)
$4* frac{1}{4}+ frac{1}{8} -1 = frac{4}{4} + frac{1}{8} -1= 1 frac{1}{8} -1=frac{1}{8}$

$4*( frac{1}{4}+ frac{1}{8}) -1= 4*( frac{2+1}{8})-1= = frac{4*3}{1*8} -1= frac{3}{2} - frac{2}{2} = frac{1}{2}$

в)
$3:6+ frac{1}{4} *(3- frac{1}{2} )= frac{1}{2} + frac{1}{4} * 2 frac{1}{2} = = frac{1}{2} + frac{1*5}{4*2} = frac{4+5}{8} = 1frac{1}{8}$

$3:6+ frac{1}{4} *3- frac{1}{2} = frac{1}{2} + frac{3}{4} - frac{1}{2} = frac{3}{4}$

г)
$2:12 +( frac{5}{6} - frac{7}{12} ) * frac{1}{7} = frac{2}{12} +( frac{10-7}{12} )* frac{1}{7} = =frac{1}{6} + frac{3*1}{12*7} = frac{1}{6} + frac{1*1}{6*7} = = frac{7}{42} + frac{1}{42} = frac{8}{42} = frac{4}{21}$

$2:12 + frac{5}{6} - frac{7}{12} * frac{1}{7}= frac{1}{6} + frac{5}{6} - frac{1}{12} = 1- frac{1}{12} = frac{11}{12}$