Bài 1:
a) \(\dfrac{11}{12}=\dfrac{11\times4}{12\times4}=\dfrac{44}{48}\) ; \(\dfrac{7}{48}\)
b) \(\dfrac{9}{50}=\dfrac{9\times4}{50\times4}=\dfrac{36}{200}\) ; \(\dfrac{61}{200}\)
c) \(\dfrac{1}{3}=\dfrac{1\times15}{3\times15}=\dfrac{15}{45}\) ; \(\dfrac{2}{15}=\dfrac{2\times3}{15\times3}=\dfrac{6}{45}\) ; \(\dfrac{4}{45}\)
Bài 2:
a) \(4=\dfrac{48}{12}\) ; \(\dfrac{9}{4}=\dfrac{9\times3}{4\times3}=\dfrac{27}{12}\)
b) \(\dfrac{5}{8}=\dfrac{5\times3}{8\times3}=\dfrac{15}{24}\) ; \(\dfrac{25}{30}=\dfrac{5}{6}\) | \(\dfrac{5}{6}=\dfrac{5\times4}{6\times4}=\dfrac{20}{24}\) ; \(2=\dfrac{48}{24}\)
Bài 3:
a) \(\dfrac{8\times3\times4}{16\times3}=\dfrac{8\times3\times4}{8\times2\times3}=\dfrac{4}{2}=2\)
b) \(\dfrac{30\times25\times7\times8}{75\times8\times12\times14}=\dfrac{2\times5\times3\times25\times7\times8}{25\times3\times8\times6\times2\times7\times2}=\dfrac{5}{6\times2}=\dfrac{5}{12}\)
