perhaps you are referring to the universal principle that matter can not be created or destroyed, only converted. if what you mean is that mathematically if matter plus matter equals a transformation and that matter minus matter equals destruction then the expression is wrong. matter taken away from matter might be seen as splitting an orange in two which is not destruction but is still 1-1.
i see, so you would mean if soda = 1 then soda minus soda would just mean taking the soda out of existence which is impossible and that taking a bit of it away is still just separation and not destruction, in which case you may be right. however destruction is not limited to merely erasing its existence ( subtracting soda from reality).
if the soda were to be sucked into a black hole it would compress and become one with the singularity, if i were to send the soda 10 years into the future, it would cease to exist in the present and for the next 10 years. if i were to teleport it into a parallel dimension and switch its mass with equal mass from this other universe the soda would cease to exist in our universe and so = 0. the concept of destruction isn't limited to destroying something to nothing.