[tex]M = \Big\{x\in \mathbb_{N}\Big| $ $ x\leq 69\Big\} \\ \\ x\leq 69 \Rightarrow x \in (-\infty, 69], $ $ $dar,$ $ $ x\in \mathbb_{N} \Rightarrow$ $x\in\Big\{0,1,2,3,...,69\Big\} \Rightarrow \\ \\ \Rightarrow M = \Big\{0,1,2,3,...,69\Big\} \Rightarrow \boxed{ card M = 70}[/tex]
