Explicação passo-a-passo:

[tex]( \frac{2}{5} + \frac{1}{5} ) \div ( \frac{1}{4} + \frac{2}{4} ) = \\ \\ ( \frac{2 + 1}{5} ) \div ( \frac{1 + 2}{4} ) = \\ \\ \frac{3}{5} \div \frac{3}{4} = \\ \\ \frac{3}{5} \times \frac{4}{3} = \\ \\ \frac{1}{5} \times \frac{4}{1} = \frac{4}{5} [/tex]

[tex]( \frac{1}{3} - \frac{1}{4} ) \div ( \frac{2}{5} - \frac{1}{10} ) = \\ \\ ( \frac{(4 \times 1) - (3 \times 1)}{3 \times 4} ) \div ( \frac{(2 \times 2) - 1}{10} ) = \\ \\ (\frac{4 - 3}{12} ) \div ( \frac{4 - 1}{10} ) = \\ \\ \frac{1}{12} \div \frac{3}{10} = \\ \\ \frac{1}{12} \times \frac{10}{3} = \\ \\ \frac{1}{6} \times \frac{5}{3} = \\ \\ \frac{5}{18} [/tex]

[tex]( \frac{2}{7} \times \frac{1}{4} ) \div ( \frac{3}{4} - \frac{1}{5} ) = \\ \\ (\frac{1}{7} \times \frac{1}{2} ) \div ( \frac{(5 \times 3) - (4 \times 1)}{4 \times 5} ) = \\ \\ \frac{1}{14} \div ( \frac{15 - 4}{20} ) = \\ \\ \frac{1}{14} \div \frac{11}{20} = \\ \\ \frac{1}{14} \times \frac{20}{11} = \\ \\ \frac{1}{7} \times \frac{10}{11} = \\ \\ \frac{10}{77} [/tex]

[tex](2 - \frac{1}{3} ) \times ( \frac{3}{4} \div \frac{5}{6} ) = \\ \\ ( \frac{(3 \times 2) - 1}{3} ) \times ( \frac{3}{4} \times \frac{6}{5} ) = \\ \\ ( \frac{6 - 1}{3} ) \times ( \frac{3}{2} \times \frac{3}{5} ) = \\ \\ \frac{5}{3} \times \frac{9}{10} = \\ \\ \frac{1}{1} \times \frac{3}{2} = \\ \\ \frac{3}{2} [/tex]