Is there a bound for $|a+b|$ of the form $f(a,b) \leq |a+b|$

Question

$a,b$ are integers and the $f(a,b)$ is a function of $a$ and $b$.

I know that $|a+b| \leq |a|+|b|$. But what about $(? \leq |a+b|)$

Answer 1

You are thinking of the reverse triangle inequality: $$||a|-|b|| \leq |a-b|.$$