3) \(10\frac{8}{9}+2\frac{4}{9}\)

\(10+2=12\), \(\frac{8}{9}+\frac{4}{9}=\frac{12}{9}=1\frac{1}{3}\).

\(12+1\frac{1}{3}=13\frac{1}{3}\).

Ответ: \(13\frac{1}{3}\).