Đáp án:
`4/3`
Giải thích các bước giải:
$\rm\#Japanese\\ \dfrac{\dfrac{1}{6}-\dfrac{1}{39}+\dfrac{1}{51}}{\dfrac{1}{8}-\dfrac{1}{52}+\dfrac{1}{68}}\\=\dfrac{\dfrac{4}{24}-\dfrac{4}{156}+\dfrac{4}{204}}{\dfrac{3}{24}-\dfrac{3}{156}+\dfrac{3}{204}}\\=\dfrac{4\times\left(\dfrac{1}{24}+\dfrac{1}{156}+\dfrac{1}{204}\right)}{3\times\left(\dfrac{1}{24}+\dfrac{1}{156}+\dfrac{1}{204}\right)}\\=\dfrac{4}{3}\times\dfrac{\dfrac{1}{24}+\dfrac{1}{156}+\dfrac{1}{204}}{\dfrac{1}{24}+\dfrac{1}{156}+\dfrac{1}{204}}\\=\dfrac{4}{3}\times1\\=\dfrac{4}{3}$