Tính nhanh: 2/3 x 4/5 x 5/6

\(\left( {\frac{2}{3} \times \frac{4}{5}} \right) \times \frac{5}{6} = \frac{2}{3} \times \frac{4}{5} \times \frac{5}{6} = \frac{{2 \times 4 \times 5}}{{3 \times 5 \times 6}} = \frac{{2 \times 2 \times 2 \times 5}}{{3 \times 5 \times 3 \times 2}} = \frac{4}{9}\).