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- Hướng dẫn giải

$$\begin{gathered} \frac{5.18-10.27+15.36}{10.36-20.54+30.72} \\ =\frac{5.18-\mathrm{5.18.3}+\mathrm{5.18.6}}{10.36-\mathrm{10.36.3}+\mathrm{10.36.6}} \\ =\frac{5.18(1-3+6)}{10.36(1-3+6)} \\ =\frac{1}{4} \end{gathered}$$