Nối phép tính với kết quả tương ứng.

Giải thích

\[\frac{2}{5} + \frac{3}{{10}} = \frac{4}{{10}} + \frac{3}{{10}} = \frac{7}{{10}}\];                                           \[\frac{1}{2} - \frac{3}{{20}} = \frac{{10}}{{20}} - \frac{3}{{20}} = \frac{7}{{20}}\]

\[\frac{5}{2} - \frac{3}{4} = \frac{{10}}{4} - \frac{3}{4} = \frac{7}{4}\];                                                \[\frac{7}{8}\,\, + \,\,\frac{3}{4} = \frac{7}{8} + \frac{6}{8} = \frac{{13}}{8}\]