What is the IUPAC name of the following compound?

$\displaystyle 3$-Bromo-$\displaystyle 3$-methyl-$\displaystyle 1$, $\displaystyle 2$-dimethylprop-$\displaystyle 1$-ene

$\displaystyle 3$-Bromo-$\displaystyle 1$, $\displaystyle 2$-dimethylbut-$\displaystyle 1$-ene

$\displaystyle 4$-Bromo-$\displaystyle 3$-methylpent-$\displaystyle 2$-ene

$\displaystyle 2$-Bromo-$\displaystyle 3$-methylpent-$\displaystyle 3$-ene