`3/5 + 1/5 : 3`
`= 3/5 + 1/15`
`= 2/3`.
`7/12 - 4/3 xx 2/9`
`= 7/12 xx 8/27`
`= 14/81`.
\(\dfrac{3}{5}+\dfrac{1}{5}\times\dfrac{1}{3}=\dfrac{3}{5}+\dfrac{1}{15}=\dfrac{9}{15}+\dfrac{1}{15}=\dfrac{10}{15}=\dfrac{2}{3}\)
\(\dfrac{7}{12}-\dfrac{8}{27}=\dfrac{63}{108}-\dfrac{32}{108}=\dfrac{31}{108}\)
2/3
14/81
tui IQ 80 nên ngu lắm sai ráng chịu
\(\dfrac{3}{5}+\dfrac{1}{5}:3\)
\(=\dfrac{3}{5}+\dfrac{1}{5}:\dfrac{3}{1}\)
\(=\dfrac{3}{5}+\dfrac{1}{5}\times\dfrac{1}{3}\)
\(=\dfrac{3}{5}+\dfrac{1}{15}\)
\(=\dfrac{9}{15}+\dfrac{1}{15}\)
\(=\dfrac{10}{15}=\dfrac{2}{3}\)
