Giải câu 4 trang 105 toán VNEN 4 tập 2.
$\frac{2}{9}+ x = 1$ $x= 1 - \frac{2}{9}$ $x= \frac{9}{9}-\frac{2}{9}=\frac{7}{9}$ | $\frac{6}{7}-x=\frac{2}{3}$ $x=\frac{6}{7}-\frac{2}{3}$ $x=\frac{18}{21}-\frac{14}{21}=\frac{4}{21}$ | $x-\frac{3}{2}=\frac{5}{6}$ $x=\frac{5}{6}+\frac{3}{2}$ $x=\frac{5}{6}+\frac{9}{6}=\frac{15}{6}$ |
$\frac{2}{5}\times x=\frac{2}{3}$ $x=\frac{2}{3}:\frac{2}{5}$ $x=\frac{2}{3}\times \frac{5}{2}=\frac{10}{6}$ | $\frac{2}{5}:x=\frac{1}{3}$ $x=\frac{2}{5}:\frac{1}{3}$ $x=\frac{2}{5}\times 3=\frac{6}{5}$ | $x :\frac{5}{11}= 22$ $x= 22 \times \frac{5}{11}$ $x=\frac{110}{11}$ |