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$\renewcommand{\d}{\displaystyle}\newcommand{\N}{\mathbb N}\newcommand{\st}{:}\renewcommand{\v}{\vtx{above}{}}\newcommand{\lt}{<}$

Let $A = \{x \in \N \st 4 \le x \lt 12\}$ and $B = \{x \in \N \st x \text{ is even}\}\text{.}$