Question

\(1/4*5/12+5/12*4/5 \) tính bằng hai cách

 

Answer 1

\(\dfrac{1}{4}\times\dfrac{5}{12}+\dfrac{5}{12}\times\dfrac{4}{5}=\dfrac{5}{12}\times\left(\dfrac{1}{4}+\dfrac{4}{5}\right)=\dfrac{5}{12}\times\left(\dfrac{5}{20}+\dfrac{8}{20}\right)=\dfrac{5}{12}\times\dfrac{13}{20}=\dfrac{13}{48}\)

Answer 2

\(C_1:\dfrac{1}{4}\times\dfrac{5}{12}+\dfrac{5}{12}\times\dfrac{4}{5}=\dfrac{5}{48}+\dfrac{1}{3}=\dfrac{7}{16}\)

\(C_2:\dfrac{1}{4}\times\dfrac{5}{12}+\dfrac{5}{12}\times\dfrac{4}{5}=\dfrac{5}{12}\times\left(\dfrac{1}{4}+\dfrac{4}{5}\right)=\dfrac{5}{12}\times\dfrac{21}{20}=\dfrac{7}{16}\)