Trong các phép tính dưới đây, phép tính có kết quả bé nhất là:

3/11

\(\frac{4}{3}\,\, \times \,\,\frac{6}{7}\)

\(\frac{8}{5}\,\, + \,\,\frac{4}{7}\)

\(\frac{{17}}{{21}}\,\,:\,\,\frac{5}{3}\)

\(\frac{9}{7}\,\, - \,\,\frac{3}{5}\)

Giải thích

Đáp án đúng là: C

A. \(\frac{4}{3}\,\, \times \,\,\frac{6}{7}\,\, = \,\,\frac{{24}}{{21}}\,\, = \,\,\frac{8}{7}\) \( = \,\,\frac{{8\,\, \times \,\,5}}{{7\,\, \times \,\,5}}\,\, = \,\,\frac{{40}}{{35}}\)

B. \(\frac{8}{5}\,\, + \,\,\frac{4}{7}\,\, = \,\,\frac{{56}}{{35}}\,\, + \,\,\frac{{20}}{{35}}\,\, = \,\,\frac{{76}}{{35}}\)

C. \(\frac{{17}}{{21}}\,\,:\,\,\frac{5}{3}\,\, = \,\,\frac{{17}}{{21}}\,\, \times \,\,\frac{3}{5}\,\, = \,\,\frac{{17}}{{35}}\)

D. \(\frac{9}{7}\,\, - \,\,\frac{3}{5}\,\, = \,\,\frac{{45}}{{35}}\,\, - \,\,\frac{{21}}{{35}}\,\, = \,\,\frac{{24}}{{35}}\)

So sánh: \(\frac{{17}}{{35}}\) < \(\frac{{24}}{{35}}\) < \(\frac{{40}}{{35}}\)< \(\frac{{76}}{{35}}\)

Vậy phép tính có kết quả bé nhất là: \(\frac{{17}}{{21}}\,\,:\,\,\frac{5}{3}\)