In Newtonian physics, it commonly assumed that conservations of linear momentum and angular momentum are independent. This paper shows the gradient of the angular momentum field is populated by components of linear momentum, which allows calculation of linear momentum from a few angular momentum values displaced an arbitrary distance. Therefore conservation of linear momentum is a necessary condition for full conservation of angular momentum (unchanging angular momentum at every (x,y,z), with unchanging gradient).These results are shown to be equally valid under left hand convention.Examples analyzed include a body orbiting in a central force, which has angular momentum changing at every observation point but one, contrasted with actual conservation of angular momentum (unchanging at every observation point, in every frame of reference). Translating angular momentum of the center of mass within and between frames of reference are discussed. A Python script is provided, to conveniently generate and evaluate random groups of particles.