\(A=\dfrac{\dfrac{2}{3}+\dfrac{2}{5}-\dfrac{2}{9}}{\dfrac{4}{3}+\dfrac{4}{5}-\dfrac{4}{9}}\\ A=\left(\dfrac{2}{3}+\dfrac{2}{5}-\dfrac{2}{9}\right):\left(\dfrac{4}{3}+\dfrac{4}{5}-\dfrac{4}{9}\right)\\ A=\left(\dfrac{30}{45}+\dfrac{18}{45}-\dfrac{10}{45}\right):\left(\dfrac{60}{45}+\dfrac{36}{45}-\dfrac{20}{45}\right)\\ A=\dfrac{38}{45}:\dfrac{76}{45}\\ A=\dfrac{38}{76}\)

a: \(V=1,5\times0,8\times1=1,2\left(m^3\right)\)

b: \(7dm=0,7m\\ V=1,5\times0,8\times0,7=0,84\left(m^3\right)\)

c:\(\text{ S cần dán giấy : }\left(1,5+0,8\right)\times2\times1=4,6\left(m^2\right)\)

7560

\(=\dfrac{4}{12}+\dfrac{2}{12}+\dfrac{1}{12}=\dfrac{7}{12}\)

\(Sxq=\left(1,8+1,6\right)\times2\times0,6=4,08\left(dm^2\right)\\ Stp=4,08+\left(1,8\times1,6\times2\right)=9,84\left(dm^2\right)\)