Rút gọn.                   a) \(\frac{{ - 16}}{{72}}\)b) \(\frac{{4.15}}{{3.12}}\)

* Hướng dẫn giải

a) \(\frac{{ - 16}}{{72}} = \frac{{ - 16:8}}{{72:8}} = \frac{{ - 2}}{9}\)

b) \(\frac{{4.15}}{{3.12}} = \frac{{4.3.5}}{{3.4.3}} = \frac{5}{3}\)