в) $$(4 \frac{1}{2} - 2 \frac{3}{4}) : 1 \frac{1}{8}$$

$$(4 \frac{1}{2} - 2 \frac{3}{4}) : 1 \frac{1}{8} = (\frac{9}{2} - \frac{11}{4}) : \frac{9}{8} = (\frac{9 \cdot 2}{2 \cdot 2} - \frac{11}{4}) : \frac{9}{8} = (\frac{18}{4} - \frac{11}{4}) : \frac{9}{8} = \frac{7}{4} : \frac{9}{8} = \frac{7}{4} \cdot \frac{8}{9} = \frac{7 \cdot 8}{4 \cdot 9} = \frac{7 \cdot 2}{1 \cdot 9} = \frac{14}{9} = 1 \frac{5}{9}$$

Ответ: $$1 \frac{5}{9}$$