I want to explicitly show that when applying a formula certain variables on LHS of the equation are very small and will not be used in computing the RHS. I was curious if there is an actual notation for that.
E.g., $A + \frac{C}{D} \approx B$ where $A$ is so small it's insignificant in the context. Is there something I can replace $A$ with to show explicitly that this variable is the one which get's omitted.