`#Mon`
`\text{ Câu 1:}`
`a)\frac{5}{8}xx4xx\frac{1}{2}`
`=\frac{5}{8}xx\frac{1x4}{2}`
`=\frac{5}{8}xx\frac{4}{2}`
`=\frac{5xx4}{8xx2}`
`=\frac{20}{16}`
`=\frac{20:4}{16:4}`
`=\frac{5}{4}`
`=>\text{ Chọn B}`
`b)\frac{7}{15}:\frac{11}{45}`
`=\frac{7}{15}xx\frac{45}{11}`
`=\frac{7xx45}{15xx11}`
`=\frac{315}{165}`
`=\frac{21}{11}`
`=>\text{ Không có đáp án đúng nhất}`
