Câu 7 (Trang 43 Cánh Diều toán lớp 6 tập 2)a)$\frac{17}{8}$ : ($\frac{27}{8}$...

b) \frac{28}{15} \times \frac{1}{4^{2}} \times 3 + (\frac{8}{15} - \frac{69}{60} \times \frac{5}{23}) : \frac{51}{54} = \frac{28}{15} \times \frac{1}{16} \times 3 + (\frac{8}{15} - \frac{23}{20} \times \frac{5}{23}) : \frac{17}{18} = \frac{7}{5} \times \frac{1}{16} \times 3 + (\frac{8}{15} - \frac{1}{4}) : \frac{17}{18} = \frac{21}{80} + (\frac{8}{15} - \frac{1}{4}) \times \frac{18}{17} = \frac{21}{80} + (\frac{8}{15} - \frac{15}{60}) \times \frac{18}{17} = \frac{21}{80} + (\frac{32}{60} - \frac{15}{60}) \times \frac{18}{17} = \frac{21}{80} + \frac{17}{60} \times \frac{18}{17} = \frac{21}{80} + \frac{3}{10} = \frac{63 + 24}{240} = \frac{87}{240} = \frac{29}{80}

a) \frac{17}{8} : (\frac{27}{8} + \frac{11}{2}) = \frac{17}{8} : (\frac{27}{8} + \frac{22}{8}) = \frac{17}{8} : \frac{49}{8} = \frac{17}{8} \times \frac{8}{49} = \frac{17}{49}