`@` `\text {Ans}` `\downarrow` `1)` \(A=\dfrac{5}{7}+\dfrac{3}{4}+\dfrac{1}{5}+\dfrac{2}{7}+\dfrac{1}{4}\) `=` \(\left(\dfrac{5}{7}+\dfrac{2}{7}\right)+\left(\dfrac{3}{4}+\dfrac{1}{4}\right)+\dfrac{1}{5}\) `=` \(1+1+\dfrac{1}{5}=\dfrac{11}{5}\) Vậy, `A=` \(\dfrac{11}{5}\) `2)` \(B=4\dfrac{4}{9}\div\dfrac{8}{3}+\dfrac{2}{3}\div2\dfrac{2}{3}\) `=` \(\dfrac{40}{9}\times\dfrac{3}{8}+\dfrac{2}{3}\times\dfrac{3}{8}\) `=` \(\dfrac{3}{8}\times\left(\dfrac{40}{9}+\dfrac{2}{3}\right)\) `=` \(\dfrac{3}{8}\times\dfrac{46}{9}=\dfrac{23}{12}\) Vậy, `B =` \(\dfrac{23}{12}\) `3)` \(C=\dfrac{2}{15}\times\dfrac{13}{27}+\dfrac{2}{15}\times\dfrac{14}{27}\) `=` \(\dfrac{2}{15}\times\left(\dfrac{13}{27}+\dfrac{14}{27}\right)\) `=` \(\dfrac{2}{15}\times1=\dfrac{2}{15}\) Vậy, `C=` \(\dfrac{2}{15}\) `4)` \(D=40,35+112,37-18,35+17,63\) `=` \(\left(40,35-18,35\right)+\left(112,37+17,63\right)\) `= 22+130` `= 152` Vậy, `D = 152.` Câu trả lời: `@` `\text {Ans}` `\downarrow` `1)` \(A=\dfrac{5}{7}+\dfrac{3}{4}+\dfrac{1}{5}+\dfrac{2}{7}+\dfrac{1}{4}\) `=` \(\left(\dfrac{5}{7}+\dfrac{2}{7}\right)+\left(\dfrac{3}{4}+\dfrac{1}{4}\right)+\dfrac{1}{5}\) `=` \(1+1+\dfrac{1}{5}=\dfrac{11}{5}\) Vậy, `A=` \(\dfrac{11}{5}\) `2)` \(B=4\dfrac{4}{9}\div\dfrac{8}{3}+\dfrac{2}{3}\div2\dfrac{2}{3}\) `=` \(\dfrac{40}{9}\times\dfrac{3}{8}+\dfrac{2}{3}\times\dfrac{3}{8}\) `=` \(\dfrac{3}{8}\times\left(\dfrac{40}{9}+\dfrac{2}{3}\right)\) `=` \(\dfrac{3}{8}\times\dfrac{46}{9}=\dfrac{23}{12}\) Vậy, `B =` \(\dfrac{23}{12}\) `3)` \(C=\dfrac{2}{15}\times\dfrac{13}{27}+\dfrac{2}{15}\times\dfrac{14}{27}\) `=` \(\dfrac{2}{15}\times\left(\dfrac{13}{27}+\dfrac{14}{27}\right)\) `=` \(\dfrac{2}{15}\times1=\dfrac{2}{15}\) Vậy, `C=` \(\dfrac{2}{15}\) `4)` \(D=40,35+112,37-18,35+17,63\) `=` \(\left(40,35-18,35\right)+\left(112,37+17,63\right)\) `= 22+130` `= 152` Vậy, `D = 152.`