Ah, math is a form of equalivence. E-MC^2 = 0.
It is about relating truths given to be by mathematical symbols that are used, even if it is Calculus and formed in a few months from a genius like Isaac Newton. Those truths or axioms are thought of as being the only truths the math can prove. In other words, 4 does not equal 5. 2 + 2 does equal 4. It is a Set of symbols used but zero had to be invented to mean nothing or not any thing or the equalivence of having 'nothing'. In other words, if you have 2 oranges and you give them both to someone as food, then you end up having no oranges when you are done and zero is the term used to indicate that.
Time is a measurement, so far, because it is thought of being that way, but since you are alive, all of us are "Time Travelers" in the sense that every time the Earth makes an orbit around the Sun, we all say that we became a year older and according to the current Calendar that is in use, which all is a standard that is used to give it a meaning, but actually a year is related to where the stars are at since they are very far away and take many many many more years to move to where anyone can state that they did move, and those stars do. In 500,000 years Acturus will no longer be a star in our skys at night. It will take that long to move, and with the naked eye we will no longer be able to look up and see it.