Oxidation states of Iron in ${\mathrm{Fe}}_3{\mathrm{O}}_4$ are

${\mathrm{Fe}}_3{\mathrm{O}}_4$  is a mixed oxide ;

It exists as ${\mathrm{Fe}}_2{\mathrm{O}}_3.\mathrm{FeO}$ ;

Two $\mathrm{Fe}$ atoms will have “+3” state ;

One $\mathrm{Fe}$ atom will have “+2” state .