$$=\frac{3}{7}+\frac{4}{7}$$

$$=1\frac{5}{7}-3\frac{4}{7}$$

$$=1\frac{3}{4}-3\frac{1}{4}$$

$$=5\frac{5}{9}-8\frac{1}{9}$$

$$....=\frac{3}{10}\times\frac{5}{6}$$

$$....=\frac{4}{15}\times\frac{5}{8}$$

$$....=\frac{6}{25}\times\frac{5}{12}$$

$$....=\frac{6}{2}\times\frac{8}{3}$$

$$....=\frac{4}{7}\div\frac{2}{3}$$

$$....=\frac{4}{10}\div\frac{2}{5}$$