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

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

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

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