This work presents an exact and compact formula for the probability of rotation-xor differentials (RX-differentials) through modular addition. for arbitrary rotation amounts. which has been a long-standing open problem. The formula comes with a rigorous proof and is also verified by extensive experiments. https://www.roneverhart.com/Vive-Health-Dorsal-Night-Splint-Alleviates-Plantar-Fasciitis-Pain/