We present a package
MixedMultiplicity for computing mixed multiplicities
of ideals in a Noetherian ring which is either local or a standard graded
algebra over a field. This enables us to find mixed volumes of convex lattice
polytopes and sectional Milnor numbers of hypersurfaces with an isolated
singularity. The algorithms make use of the defining equations of the multi-Rees
algebra of ideals, which are obtained by generalising a result of Cox, Lin and
Sosa.