A method for calculating cascade schemes with several external flows is proposed. The method generalizes well-known ones. Its efficiency tested on the calculations on the concentration of 183W in the additional flow. The case of feeding a cascade of regenerated fuel from light water reactors, uranium from the waste fuel of the industrial reactors and depleted ura nium for enrichment to the required concentration of 235U in the product is considered as well. Using the example of xenon isotope mixture separation, the possibility of simultaneous concentration of two target components in a cascade with two additional products is shown