Tính bằng cách thuận tiện nhất:
a,1\(\dfrac{1}{3}\) x 1\(\dfrac{1}{4}\) x 1\(\dfrac{1}{5}\) : 1\(\dfrac{1}{6}\) x 1\(\dfrac{1}{7}\) x1\(\dfrac{1}{8}\) = b, 1\(\dfrac{1}{3}\) : 1\(\dfrac{1}{4}\) : 1\(\dfrac{1}{5}\) : 1\(\dfrac{1}{6}\) : 1\(\dfrac{1}{7}\) :1\(\dfrac{1}{8}\) =