Question

5/8x20/9+5/8x7/9+ 1 và 5/8

Answer 1

\(\dfrac{5}{8}\times\dfrac{20}{9}-\dfrac{5}{8}\times\dfrac{7}{9}+1\)

\(=\dfrac{5}{8}\times\left(\dfrac{20}{9}-\dfrac{7}{9}\right)+1\)

\(=\dfrac{5}{8}\times\dfrac{13}{9}+1\)

\(=\dfrac{65}{72}\)

Ta có: \(\dfrac{5}{8}=\dfrac{45}{72}\)

Mà: \(65>45\)

Vậy: \(\dfrac{65}{72}>\dfrac{45}{72}\) hay \(\dfrac{5}{8}\times\dfrac{20}{9}+\dfrac{5}{8}\times\dfrac{7}{9}+1>\dfrac{5}{8}\)