Số đối của số hữu tỉ $\frac{-22}{23}$ 1\frac{4}{23}+\frac{5}{21}-\frac{4}{23}+0,5+\frac{16}{21}$$ \sqrt{\frac{25}{81}}:2\frac{2}{5}-4\frac{5}{9}:2\frac{2}{5}$$ 6.{\left(-\frac{-1}{2}\right)}^2+\frac{3}{5}$$ 1\frac{4}{23}+\frac{5}{21}-\frac{4}{23}+0,5+\frac{16}{21}$$ \sqrt{\frac{25}{81}}:2\frac{2}{5}-4\frac{5}{9}:2\frac{2}{5}$$ 6.{\left(-\frac{-1}{2}\right)}^2+\frac{3}{5}$$ \frac{7}{30}$$ \frac{5}{18}$$ \frac{2}{3}$$ \frac{x-1}{x+5}=\frac{6}{7}$$ \frac{}{}$$ \frac{}{}$$ \frac{2}{5}+\frac{1}{5}.\left(\frac{-3}{4}\right)=\frac{3}{5}.\left(\frac{-3}{4}\right)$$ {\left(-3\right)}^2.\left(\frac{3}{4}-0,25\right)-\left(3\frac{1}{2}-1\frac{1}{2}\right)$$ k$$ \frac{1}{{\sin }^2\frac{\pi }{4k+2}}+\frac{1}{{\sin }^2\frac{3\pi }{4k+2}}+\frac{1}{{\sin }^2\frac{5\pi }{4k+2}}+\cdots +\frac{1}{{\sin }^2\frac{(2k-1)\pi }{4k+2}}=2k(k+1$$ \frac{-1}{5}<\frac{1}{1000}$$ \frac{267}{-268}>\frac{-1347}{1343}$$ \frac{-13}{38}<\frac{29}{-88}$$ \frac{-18}{31}=\frac{-181818}{313131}$$ \frac{1}{2},\frac{2}{3},\frac{3}{4}$$ \frac{x}{15}=\frac{-2}{3,5}$$ \frac{16}{x}=\frac{x}{25}$$ \frac{0,5}{0,7}=\frac{-0,1}{5x}$$ \frac{x}{5}=\frac{y}{25}$$ 5x=3y$$ \frac{x}{2}=\frac{y}{4}=\frac{z}{6}$$ \frac{x}{3}=\frac{y}{4};\frac{y}{6}=\frac{z}{8}$$ \frac{x}{3}=\frac{y}{4}=\frac{z}{5}$$ \frac{x}{3}=\frac{y}{7}=\frac{z}{2}$$ 2x^2+y^2+3z^2=316$$ \frac{2}{3x+1}$$ \frac{x}{7}+\frac{y}{11}+\frac{z}{13}=0,\left(946053\right)$$