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\begin{align*} \begin{aligned} P(X \text { is even }) &=P(2)+P(4)+P(6)+P(8)+P(10)+P(12) \\ &=\frac{1}{36}+\frac{3}{36}+\frac{5}{36}+\frac{5}{36}+\frac{3}{36}+\frac{1}{36}=\frac{18}{36}=0.5 \end{aligned} \end{align*}