Bài 1:
\(a,MSC:30\\ \dfrac{5}{6}=\dfrac{5\times5}{6\times5}=\dfrac{25}{30}\\ \dfrac{2}{5}=\dfrac{2\times6}{5\times6}=\dfrac{12}{30}\\ b,MSC:72\\ \dfrac{7}{8}=\dfrac{7\times9}{8\times9}=\dfrac{63}{72}\\ \dfrac{4}{9}=\dfrac{4\times8}{9\times8}=\dfrac{32}{72}\\ c,MSC:143\\ \dfrac{9}{11}=\dfrac{9\times13}{11\times13}=\dfrac{117}{143}\\ \dfrac{10}{13}=\dfrac{10\times11}{13\times11}=\dfrac{110}{143}\)
Bài 2:
\(a,MSC:42\\ \dfrac{9}{14}=\dfrac{9\times3}{14\times3}=\dfrac{27}{42}\\ \dfrac{5}{21}=\dfrac{5\times2}{21\times2}=\dfrac{10}{42}\\ b,MSC:48\\ \dfrac{5}{24}=\dfrac{5\times2}{24\times2}=\dfrac{10}{48}\\ \dfrac{9}{16}=\dfrac{9\times3}{16\times3}=\dfrac{27}{48}\\ c,MSC:150\\ \dfrac{8}{15}=\dfrac{8\times10}{15\times10}=\dfrac{80}{150}\\ \dfrac{7}{25}=\dfrac{7\times6}{25\times6}=\dfrac{42}{150}\)
