Giải câu 6 trang 12 toán VNEN 7 tập 1 .
A = (6 - $\frac{2}{3}$ + $\frac{1}{2}$) - (5 + $\frac{5}{3}$ - $\frac{3}{2}$) - (3 - $\frac{7}{3}$ + $\frac{5}{2}$)
= 6 - $\frac{2}{3}$ + $\frac{1}{2}$ - 5 - $\frac{5}{3}$ + $\frac{3}{2}$ - 3 + $\frac{7}{3}$ - $\frac{5}{2}$
= (6 - 5 - 3) - ($\frac{2}{3}$ + $\frac{5}{3}$ - $\frac{7}{3}$) + ($\frac{1}{2}$ + $\frac{3}{2}$ - $\frac{5}{2}$)
= -2 - 0 + ($\frac{-1}{2}$) = -2 - $\frac{1}{2}$ = - $\frac{4}{2}$ - $\frac{1}{2}$ = - $\frac{5}{2}$.
Vậy A = - $\frac{5}{2}$