Phần II. Tự luận Tính a) ( frac{2}{5} + frac{6}{7} ) = …………………………………………………………………………… b) ( frac{7}{4} - frac{3}{8} ) = …………………………………………………………………………… c) 5 + ( frac{2}{7} ) = ………………………………………………………………………...

a) ( frac{2}{5} + frac{6}{7} = frac{{14}}{{35}} + frac{{30}}{{35}} = frac{{14 + 30}}{{35}} = frac{{44}}{{35}} ) b) ( frac{7}{4} - frac{3}{8} = frac{{56}}{{32}} - frac{{12}}{{32}} = frac{{56 - 12}}{{32}} = frac{{44}}{{32}} = frac{{11}}{8} ) c) 5 + ( frac{2}{7} ) = ( frac{5}{1} + frac{2}{7} = frac{{35}}{7} + frac{2}{7} = frac{{37}}{7} ) d) 3 - ( frac{4}{3} ) = ( frac{3}{1} - frac{4}{3} = frac{9}{3} - frac{4}{3} = frac{5}{3} )