\(\dfrac{2}{9}-\left(\dfrac{1}{10}+\dfrac{2}{9}\right)=\dfrac{2}{9}-\dfrac{1}{10}-\dfrac{2}{9}=-\dfrac{1}{10}\)
2/9 - ( 1/20 + 2/9 )= 2/9 - 1/20 - 2/9 = ( 2/9 - 2/9) - 1/20 = -1/20
\(=\dfrac{2}{9}-\dfrac{1}{10}-\dfrac{2}{9}=\left(\dfrac{2}{9}-\dfrac{2}{9}\right)-\dfrac{1}{10}=-\dfrac{1}{10}\)
2/9 - ( 1/20 + 2/9 )= 2/9 - 1/20 - 2/9 = ( 2/9 - 2/9) - 1/20 = -1/20