Let $\displaystyle \epsilon>0, \delta>0$ and $\displaystyle a \in \mathbb{R}$. Show that $\displaystyle V_\epsilon(a) \cap V_\delta(a)$ and $\displaystyle V_\epsilon(a) \cup V_\delta(a)$ are $\displaystyle \gamma$-neighborhoods of $\displaystyle a$ for appropriate values of $\displaystyle \gamma$.

Any hints will be appretiate. I have a proof, but it's really simple and I doubt it's correct. Thanks!