A body immersed in a fluid is pushed up by a force equal to the weight of the fluid it displaces, so F_buoy = rho_fluid * g * V_displaced. This displaced-fluid ledger is exact only for a stated fluid density, displaced volume, gravity, static equilibrium, and simple geometry. Real measurements add body shape, wetting, density variation, scale calibration, surface motion, and uncertainty.
Buoyant force is checked from density, gravity, and displaced volume. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
Displaced fluid weight gives buoyant force
Density 2, gravity 10, and displaced volume 3 give buoyant force 60 newtons.
2×10×3=60
The upward force is a displaced-fluid ledger
The buoyant force is not a material property here; it is the 60 newton displaced-fluid weight.