Tính các phép tính sau:
Giải thích
a) \(\frac{2}{3} + \frac{3}{5}\) = \(\frac{{10}}{{15}} + \frac{9}{{15}}\) = \(\frac{{19}}{{15}}\) | \(\frac{7}{{12}} - \frac{2}{7} + \frac{1}{{12}}\) = \(\left( {\frac{7}{{12}} + \frac{1}{{12}}} \right) - \frac{2}{7}\) =\(\frac{2}{3} - \frac{2}{7} = \frac{{14}}{{21}} - \frac{6}{{21}} = \frac{8}{{21}}\) | \(\frac{{12}}{{17}} - \frac{5}{{17}} - \frac{4}{{17}}\) =\(\frac{7}{{17}} - \frac{4}{{17}}\) =\(\frac{3}{{17}}\) | |
b) 578,69 + 281,78 = 860,47
| 594,72 + 406,38 – 329,47 =1001, 1 – 329,47 = 671,63 | ||