Câu 2 :
a) 70 . ( -12 ) + ( -12 ) . 29 + ( -12 )
= 70 . ( -12 ) + ( -12 ) . 29 + ( -12 ) .1
= ( -12 ) . ( 70 + 29 + 1 )
= -12 . 100
= -1200
b ) 4 + $\frac{15}{4}$ - ( $\frac{4}{5}$ + $\frac{2}{3}$ ) : 2$\frac{1}{5}$
= 4 + $\frac{15}{4}$ - $\frac{22}{15}$ : $\frac{11}{5}$
= 4 + $\frac{15}{4}$ - $\frac{2}{3}$
= $\frac{85}{12}$