This paper develops the theory of factorial numbers formed by positional number systems with mixed-base factorial number systems. The fundamentals of the theory of factorial numbers are outlined. a method for obtaining them is given. their range is determined. https://www.diegojavierfares.com/quick-sale-Mariya-B-Lawn-Festival-Collection-Vol-3-Nx-Shree-Fabs-Lawn-Cotton-Pakistani-Readymade-Suits-Supplier-India-p30452-top-buy/