[tex] \frac{2}{3} + 0.77 = \frac{2}{3} + \frac{77}{100} = \frac{200}{300} + \frac{231}{300} = \frac{431}{300} [/tex]
[tex]1.75 - \frac{5}{6} = \frac{175}{100} - \frac{5}{6} = \frac{7}{4} - \frac{5}{6} = \frac{21}{12} - \frac{10}{12} = \frac{11}{12} [/tex]
[tex]6.4 \times \frac{4}{8} = \frac{64}{10} \times \frac{4}{8} = \frac{32}{5} \times \frac{4}{8} = \frac{4}{5} \times 4 = \frac{16}{5} = 3 \frac{1}{5} [/tex]
[tex]2.4 \div 1 \frac{3}{5} = \frac{24}{10} \div \frac{8}{5} = \frac{24}{10} \times \frac{5}{8} = \frac{12}{5} \times \frac{5}{8} = \frac{12}{8} = \frac{3}{2} [/tex]
