a , $\frac{8}{11}$ . $\frac{14}{23}$ + $\frac{9}{23}$ : $\frac{11}{8}$ - $\frac{8}{11}$
= $\frac{8}{11}$ . $\frac{14}{23}$ + $\frac{9}{23}$ . $\frac{11}{8}$ - $\frac{8}{11}$
= $\frac{8}{11}$ . ( $\frac{14}{23}$ + $\frac{11}{8}$ - 1 )
= $\frac{8}{11}$ . ( $\frac{112}{184}$ + $\frac{253}{184}$ - $\frac{184}{184}$
= $\frac{8}{11}$ . $\frac{181}{184}$
= $\frac{1448}{2024}$
( Tới đoạn này bạn tự rút gọn típ nha )
b, 1,8 - $\frac{20}{27}$ + ( 75% - $\frac{5}{16}$ ) : 3$\frac{1}{2}$
= $\frac{18}{10}$ -$\frac{20}{27}$ + ( $\frac{3}{4}$ - $\frac{5}{16}$ : $\frac{7}{2}$
= $\frac{9}{5}$ - $\frac{20}{27}$ + ( $\frac{3}{4}$ - $\frac{5}{16}$ . $\frac{2}{7}$ )
= $\frac{243}{135}$ - $\frac{100}{135}$ + ( $\frac{3}{4}$ - $\frac{5}{56}$ )
= $\frac{143}{135}$ + $\frac{37}{56}$
= $\frac{8008}{7560}$ + $\frac{41995}{7560}$
= $\frac{50003}{7560}$
( Tới đây bạn tự rút gọn nha )