a) \(\left(\frac{1}{3}-\frac{1}{5}\right)^2:\left(\frac{1}{5}\right)^2=\left[\left(\frac{1}{3}-\frac{1}{5}\right):\frac{1}{5}\right]^2=\left(\frac{2}{15}:\frac{1}{5}\right)^2=\left(\frac{2}{3}\right)^2=\frac{4}{9}\)
c)\(7\frac{1}{23}+\frac{10}{27}-5\frac{1}{23}+\frac{17}{27}+2^3=\left(7\frac{1}{23}-5\frac{1}{23}\right)+\left(\frac{10}{27}+\frac{17}{27}\right)+2^3=2+1+8=11\)
d)\(5.\left(-\frac{5}{2}\right)^2+\frac{1}{5}.\left(-3\right)^2=5.\frac{25}{4}+\frac{1}{5}.9=\frac{125}{4}+\frac{9}{5}=\frac{661}{20}\)
a) \(\left(\frac{1}{3}-\frac{1}{5}\right)^2:\left(\frac{1}{5}\right)^2=\left[\left(\frac{1}{3}-\frac{1}{5}\right):\frac{1}{5}\right]^2=\left[\left(\frac{5}{15}-\frac{3}{15}\right):\frac{1}{5}\right]^2=\left[\frac{2}{15}.5\right]^2=\left[\frac{2}{3}\right]^2=\frac{4}{9}\)
b) \(\frac{2^3.5^2.8}{10^{10}}=\frac{2^3.5^2.2^3}{\left(2.5\right)^{10}}=\frac{\left(2^3.2^3\right).5^2}{2^{10}.5^{10}}=\frac{2^6.5^2}{2^{10}.5^{10}}=\frac{1}{2^4.5^8}=\frac{1}{6250000}\)
c) \(7\frac{1}{23}+\frac{10}{27}-5\frac{1}{23}+\frac{17}{27}+2^3\)
\(=\left(7\frac{1}{23}-5\frac{1}{23}\right)+\left(\frac{10}{27}+\frac{17}{27}\right)+2^3\)
\(=2+1+8\)
\(=11\)
d) \(5.\left(-\frac{5}{2}\right)^2+\frac{1}{5}.\left(-3\right)^2\)
\(=5.\frac{25}{4}+\frac{1}{5}.9\)
\(=\frac{125}{4}+\frac{9}{5}\)
\(=\frac{625}{20}+\frac{36}{20}=\frac{661}{20}\)
Chuk bạn hok tốt ! 
