And that's because under different conditions, for example, if the temperature is different, these PKA values will be slightly different. So that's okay because this method still works for those values as well. So we have a PK of eight, 4.14.1 and three. So let's begin by applying these rules in rule number one. Step number one, we estimate the PH at which the net charge and the protein would be zero. Now, at least in the beginning, before we gain intuition about how to solve these problems, we have to actually guess.