Giải câu 3 trang 13 VEN toán 5 tập 1

$\frac{3}{5} + \frac{2}{7} = \frac{21}{35} + \frac{10}{35} = \frac{31}{35}$

$\frac{7}{9} - \frac{1}{6} = \frac{14}{18} - \frac{3}{18} = \frac{11}{18}$

$\frac{7}{8} + 3 = \frac{7}{8} + \frac{24}{8} = \frac{31}{8}$

$2 - \frac{5}{4} = \frac{8}{4} - \frac{5}{4} = \frac{3}{4}$

$\frac{9}{2} \times \frac{4}{5} = \frac{9 \times 4}{2 \times 5} = \frac{36}{10}$

$\frac{8}{7} : \frac{2}{3} = \frac{8}{7} \times \frac{3}{2} = \frac{24}{14}$

$4 \times \frac{5}{9} = \frac{4 \times 5}{1 \times 9} = \frac{20}{9}$

$\frac{3}{8} : 2 = \frac{3}{8} \times \frac{1}{2} = \frac{3}{16}$