Giải bài 1 trang 25 toán 7 tập 1 cánh diều

a. $\frac{1}{9} - 0, 3. \frac{5}{9} + \frac{1}{3}$

$= \frac{1}{9} - \frac{3}{10} . \frac{5}{9} + \frac{1}{3}$

$= \frac{1}{9} - \frac{3}{2.5} . \frac{5}{3.3} + \frac{1}{3}$

$= \frac{1}{9} - \frac{1}{6} + \frac{1}{3}$

$= \frac{2}{18} - \frac{3}{18} + \frac{6}{18} = \frac{5}{18}$

b. ${(\frac{- 2}{3})}^{2} + \frac{1}{6} - (0, 5)^{3}$

$= \frac{4}{9} + \frac{1}{6} - (\frac{- 1}{8})$

$= \frac{4}{9} + \frac{1}{6} + \frac{1}{8}$

$= \frac{32}{72} + \frac{12}{72} + \frac{9}{72} = \frac{53}{72}$