A large class of "evidences" presented by young-Earth advocates involve measuring rates of various Earth processes, then attempting to extrapolate them backwards for millions of years. Generally, the purpose is to show that the process in question would build up to absurdity if it were allowed to continue through "evolutionary timescales." The fallacy of most claims of this type is a failure to recognize the importance of equilibrium. Most processes on Earth are in a state of balance, in which one process (such as erosion of the continents) is counteracted by others (such as emplacement of new continental material by volcanoes and tectonic uplift). Generally, processes on Earth do not build up without limit, because there is always another process that opposes the build-up, leading to the establishment of equilibrium. The method for dealing with young-Earth claims of this type is to look for the limiting process that imposes equilibrium. In some cases the balancing process has simply been overlooked, and the young-Earth claim is laid to rest by pointing it out. Other times the balancing process is not well understood or even unknown, which may seem to lend credence to young-Earth claims. However, in these cases we simply revert to the Unexplained Mystery. Unless we can prove that no balancing process exists (and in most cases that cannot be done), we should adopt the working hypothesis that there is a yet-to-be-discovered process that provides the equilibrium, rather than jumping to the assumption of a supernatural explanation. Examples of the One-Sided Equation Fallacy include Influx of Magma from Mantle to Form Crust, and Erosion of Sediment from Continents, Maximum Life of Comets, and Helium-4 in the Atmosphere