\(2\dfrac{1}{3}x2\dfrac{1}{7}x2\dfrac{1}{15}x2\dfrac{1}{31}\)
\(=\dfrac{7}{3}x\dfrac{15}{7}x\dfrac{31}{15}x\dfrac{63}{31}\)
\(=\dfrac{63}{3}=21\)
\(2\dfrac{1}{3}:2\dfrac{1}{7}:2\dfrac{1}{15}:2\dfrac{1}{31}\)
\(=\dfrac{7}{3}:\dfrac{15}{7}:\dfrac{31}{15}:\dfrac{63}{31}\)
\(=\dfrac{7}{3}x\dfrac{7}{15}x\dfrac{15}{31}x\dfrac{31}{63}\)
\(=\dfrac{7x7x15x31}{3x15x31x7x9}\)
\(=\dfrac{7}{3x9}\)
\(=\dfrac{7}{27}\)
\(a,2\dfrac{1}{3}.2\dfrac{1}{7}.2\dfrac{1}{15}.2\dfrac{1}{31}\)
\(\Rightarrow\dfrac{7}{3}.\dfrac{15}{7}.\dfrac{31}{15}.\dfrac{62}{31}\)
\(\Rightarrow\dfrac{62}{3}\)
\(b,2\dfrac{1}{3}\div2\dfrac{1}{7}\div2\dfrac{1}{15}\div2\dfrac{1}{31}\)
\(\Rightarrow\dfrac{7}{3}\div\dfrac{15}{7}\div\dfrac{31}{15}\div\dfrac{62}{31}\)
\(\Rightarrow\dfrac{7}{3}.\dfrac{7}{15}.\dfrac{15}{31}.\dfrac{31}{62}\)
\(\Rightarrow\dfrac{7}{3}.7.1.\dfrac{1}{62}\)
\(\Rightarrow\dfrac{49}{186}\)
