In recent years, we used lattice QCD to calculate some quantities that were unknown or poorly known. They are the q2 dependence of the form factor in semileptonic D → Klν decay, the leptonic decay constants of the D+ and Ds mesons, and the mass of the Bc meson. In this paper, we summarize these calculations, with emphasis on their (subsequent) confirmation by measurements in e+e−, γp and p+p− collisions.