Tính bằng cách thuận tiện:
Giải thích
a) \(\frac{3}{{14}} \times \frac{{28}}{9} \times \frac{{14}}{3}\) = \((\frac{3}{{14}} \times \frac{{14}}{3}) \times \frac{{28}}{9}\) = \(1 \times \frac{{28}}{9}\) = \(\frac{{28}}{9}\) | b) \(\frac{4}{7} \times \frac{5}{8} + \frac{5}{8} \times \frac{4}{7}\) = \(\frac{4}{7} \times (\frac{5}{8} + \frac{5}{8})\) = \(\frac{4}{7} \times \frac{5}{4}\) = \(\frac{5}{7}\) |
