Đúng ghi Đ, sai ghi S.
a) \(\frac{8}{5} = \frac{{72}}{{40}}\) S b) \(\frac{{14}}{{37}} = \frac{{42}}{{111}}\) Đ
c) \(\frac{{100}}{{15}} = \frac{{20}}{3}\) Đ d) \(\frac{{200}}{{50}} = \frac{2}{5}\) S
Giải thích:
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 \[\frac{{200}}{{50}} > \frac{2}{5}\] |