\(\left(\frac{2}{9} + \left(-\frac{5}{9}\right)\right) + \frac{2}{3}\)
\(\frac{2}{9} + \left(-\frac{5}{9}\right) = \frac{2 - 5}{9} = \frac{-3}{9}\)
\(\frac{-3}{9}\) можно сократить на 3: \(\frac{-3 \div 3}{9 \div 3} = \frac{-1}{3}\)
\(\frac{-1}{3} + \frac{2}{3}\)
\(\frac{-1 + 2}{3} = \frac{1}{3}\)
Ответ: 1⁄₃