Giải câu 5 trang 38 Cánh Diều Toán 6 tập 2.
a) $\frac{27}{13}$ - $\frac{106}{111}$ + $\frac{-5}{111}$ = $\frac{27}{13}$ - ( $\frac{106}{111}$ + $\frac{5}{111}$ ) = $\frac{27}{13}$ - $\frac{111}{111}$ = $\frac{27}{13}$ - 1 = $\frac{27 - 13}{13}$ = $\frac{14}{13}$
b) $\frac{12}{11}$ - $\frac{-7}{19}$ + $\frac{12}{19}$ = $\frac{12}{11}$ - ( $\frac{-7}{19}$ - $\frac{12}{19}$ ) = $\frac{12}{11}$ - $\frac{-19}{19}$ = $\frac{12}{11}$ - (- 1) = $\frac{12}{11}$ + 1 = $\frac{12 + 11}{11}$ = $\frac{23}{11}$
c) $\frac{5}{17}$ - $\frac{25}{31}$ + $\frac{12}{17}$ + $\frac{-6}{31}$ = ( $\frac{5}{17}$ + $\frac{12}{17}$ ) - ( $\frac{25}{31}$ + $\frac{6}{31}$ ) = $\frac{17}{17}$ - $\frac{31}{31}$ = 1 -1 = 0