\(=\dfrac{4}{10}+\dfrac{3}{10}-\dfrac{5}{10}=\dfrac{2}{10}=\dfrac{1}{5}\)
\(\dfrac{2}{5}+\dfrac{3}{10}-\dfrac{1}{2}=\dfrac{4}{10}+\dfrac{3}{10}-\dfrac{5}{10}=\dfrac{4+3-5}{10}=\dfrac{2}{10}=\dfrac{1}{5}\)
`2/5 + 3/10 - 1/2`
`= 4/10 + 3/10 - 5/10`
`= 2/10`
`= 1/5`