[tex]1)8 \frac{7}{8} - 5 \frac{3}{4} = 8 \frac{7}{8} - 5 \frac{6}{8} = 3 \frac{1}{8} \\ 2)7 \frac{7}{15} - 4 \frac{5}{18} = 7 \frac{42}{90} - 4 \frac{25}{90} = 3 \frac{17}{90} \\ 3)6 \frac{11}{18} - 8 \frac{8}{27} = 16 \frac{ = 33}{54} - 8 \frac{16}{54} = 8 \frac{17}{54} \\ 4)8 \frac{17}{28} - 7 \frac{23}{42} = 8 \frac{51}{84} - 7 \frac{46}{84} = 1 \frac{5}{84} [/tex]