Tính nhanh: 3/4 × 4/5 × 5/6 × 6/7 × 7/8 × 8/9 × 9/10

\(\frac{3}{4}\times\frac{4}{5}\times\frac{5}{6}\times\frac{6}{7}\times\frac{7}{8}\times\frac{8}{9}\times\frac{9}{10}=\frac{3\times4\times5\times6\times7\times8\times9}{4\times5\times6\times7\times8\times9\times10}=\frac{3}{10}\)

3/4 × 4/5 × 5/6 × 6/7 × 7/8 × 8/9 × 9/10

= 3/5 × 5/6 × 6/7 × 7/8 × 8/9 × 9/10

= 3/6 × 6/7 × 7/8 × 8/9 × 9/10

= 3/7 × 7/8 × 8/9 × 9/10

= 3/8 × 8/9 × 9/10

= 3/9 × 9/10

3/10

= 3/10

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