Câu 1 :
a) 24 - { 12 - [ (-10) - (-2)]}
= 24 - { 12 - [ -10 + 2 ]}
= 24 - { 12 - [-8]}
= 24 - ( 12 + 8 )
= 24 - 20
= 4
b) $\frac{2}{3}$ + $\frac{1}{3}$ . ($\frac{-2}{3}$ + $\frac{5}{6}$ ) : $\frac{2}{3}$
= $\frac{2}{3}$ + $\frac{1}{3}$ . ( $\frac{-4}{6}$ + $\frac{5}{6}$ ) . $\frac{3}{2}$
= $\frac{2}{3}$ + $\frac{1}{3}$ . $\frac{1}{6}$ . $\frac{3}{2}$
= $\frac{2}{3}$ + $\frac{1}{18}$ . $\frac{3}{2}$
= $\frac{2}{3}$ + $\frac{1}{12}$
= $\frac{3}{4}$
Câu 2 :
a) $\frac{2}{5}$ + ( $\frac{5}{9}$ + $\frac{2}{5}$ )
= $\frac{2}{5}$ + $\frac{5}{9}$ + $\frac{2}{5}$
= $\frac{2}{5}$ + $\frac{2}{5}$ + $\frac{5}{9}$
= $\frac{4}{5}$ + $\frac{5}{9}$
= $\frac{61}{45}$
b) $\frac{17}{13}$ - ( $\frac{4}{13}$ - 11 )
= $\frac{17}{13}$ - $\frac{4}{13}$ + 11
= $\frac{13}{13}$ + 11
= 1 + 11
= 12
c) $\frac{3}{5}$ . $\frac{18}{17}$ + $\frac{3}{5}$ . $\frac{9}{17}$ - $\frac{3}{5}$ . $\frac{10}{17}$
= $\frac{3}{5}$ . ( $\frac{18}{17}$ + $\frac{9}{17}$ - $\frac{10}{17}$ )
= $\frac{3}{5}$ . $\frac{17}{17}$
= $\frac{3}{5}$ . 1
= $\frac{3}{5}$
