Question

Tính bằng cách thuận tiện nhất.

a) \(\dfrac{16}{15}+\dfrac{7}{15}+\dfrac{4}{15}\)                             b) \(\dfrac{5}{17}+\dfrac{7}{17}+\dfrac{13}{17}\)

Answer 1

a) \(\dfrac{16}{15}+\dfrac{7}{15}+\dfrac{4}{15}=\left(\dfrac{16}{15}+\dfrac{4}{15}\right)+\dfrac{7}{15}=\dfrac{20}{15}+\dfrac{7}{15}=\dfrac{27}{15}\)

b) \(\dfrac{5}{17}+\dfrac{7}{17}+\dfrac{13}{17}=\dfrac{5}{17}+\left(\dfrac{7}{17}+\dfrac{13}{17}\right)=\dfrac{5}{17}+\dfrac{20}{17}=\dfrac{25}{17}\)