Question

Explain why the temperature for freezing point and boiling point are the same.

Answer 1

We have to wonder what substance you're working with.  Under normal, human environmental conditions, there are almost no substances that freeze and boil at the same temperature. 

However, EVERY substance has SOME temperature, at some pressure, at which it "sublimes" ... passing directly from solid to gas, or from gas to solid, without existing in liquid form in between.  Even water does that, if the conditions are right.

Answer 2

If you are referring to the rules of Celsius, that applies. Since the freezing point of water in Celsius is 0 degrees and the boiling point of water is 100 degrees, it can be said that the to share an equal distance from each other. (100-100=0 and 0+100= 100) You would have to gain or lose 100 so they both gave the same distance from each other.