Scientists calculate wormholes using differential geometry, which involves the study of curved spaces and the mathematical properties of these geometries. Wormholes are theoretical solutions to the Einstein field equations, suggesting they could connect distant points in spacetime. The calculations often involve complex mathematical models and concepts beyond simple mental math, requiring advanced understanding of physics and mathematics. For those interested in a deeper exploration, Matt Visser's book "Lorentzian Wormholes" provides insights, even for readers who may struggle with the math. Overall, the study of wormholes remains a fascinating yet hypothetical area of research in theoretical physics.