Question

rút gọn các phân số sau :

21/28

18/54

90/72

9/36

30/48

72/42

Answer 1

\(\dfrac{21}{28}=\dfrac{21:7}{28:7}=\dfrac{3}{4}\)

\(\dfrac{18}{54}=\dfrac{18:9}{54:9}=\dfrac{2}{6}=\dfrac{1}{3}\)

\(\dfrac{90}{72}=\dfrac{90:9}{72:9}=\dfrac{10}{8}=\dfrac{5}{4}\)

\(\dfrac{9}{36}=\dfrac{9:9}{36:9}=\dfrac{1}{4}\)

\(\dfrac{30}{48}=\dfrac{30:6}{48:6}=\dfrac{5}{8}\)

\(\dfrac{72}{42}=\dfrac{72:6}{42:6}=\dfrac{12}{7}\)