Đúng ghi Đ, sai ghi S.

a) \(\frac{8}{5} = \frac{{72}}{{40}}\)                                        b) \(\frac{{14}}{{37}} = \frac{{42}}{{111}}\)   

c) \(\frac{{100}}{{15}} = \frac{{20}}{3}\)                                     d) \(\frac{{200}}{{50}} = \frac{2}{5}\)    

a) \(\frac{8}{5} = \frac{{72}}{{40}}\)

Ta có: \[\frac{{72}}{{40}} = \frac{{72:8}}{{40:8}} = \frac{9}{5}\]

So sánh: \[\frac{8}{5} < \frac{9}{5}\]

Vậy \[\frac{8}{5} < \frac{{72}}{{40}}\]

c) \(\frac{{100}}{{15}} = \frac{{20}}{3}\)

Ta có: \[\frac{{100}}{{15}} = \frac{{100:5}}{{15:5}} = \frac{{20}}{3}\]

So sánh: \[\frac{{20}}{3} = \frac{{20}}{3}\]

Vậy \[\frac{{100}}{{15}} = \frac{{20}}{3}\]

b) \(\frac{{14}}{{37}} = \frac{{42}}{{111}}\)

Ta có: \[\frac{{14}}{{37}} = \frac{{14 \times 3}}{{37 \times 3}} = \frac{{42}}{{111}}\]

So sánh: \(\frac{{42}}{{111}} = \frac{{42}}{{111}}\)

Vậy \(\frac{{14}}{{37}} = \frac{{42}}{{111}}\)

c) \(\frac{{200}}{{50}} = \frac{2}{5}\)

Ta có: \[\frac{{200}}{{50}} = \frac{{200:10}}{{50:10}} = \frac{{20}}{5}\]

So sánh: \[\frac{{20}}{5} > \frac{2}{5}\]

Vậy \[\frac{{200}}{{50}} > \frac{2}{5}\]