the intersection is simply the common data values in each set, in this case
[tex]\bf \{1,\stackrel{\downarrow }{2},3,\stackrel{\downarrow }{5}\} \cap \{0,\stackrel{\downarrow }{2},\stackrel{\downarrow }{5},7\}~\hspace{5em}\implies \{2,5\}[/tex]