19. \(\frac{11}{35}+\frac{13}{45}\)

НОК(35, 45) = 315. \(\frac{11}{35}+\frac{13}{45}=\frac{99}{315}+\frac{91}{315}=\frac{190}{315}=\frac{38}{63}\).

Ответ: \(\frac{38}{63}\).