Q: When I am looking at the membrane potential moving closer or farther away from zero mV to determine if is depolarize or hyperpolarize, am I supposes to looking at the zero mV pertain to the ECF?  

A: In general, yes, consider the ECF to be 0mv.

However, in this exercise, you don't need to know the exact number of mV on each side. You just have to know if the difference between the two sides is becoming larger or smaller.