Answer
In $Fe_{2}O_{4}$, two Fe ions have oxidation state of +3 and one ion has oxidation state of +2. In $Fe_{2}O_{3}$, oxidation state of Fe is +3.
Work Step by Step
For $Fe_{3}O_{4}$:
Fe: +3 x 2 = +6, +2 x 1 = +2, O: -2 x 4 = -8
For $Fe_{2}O_{3}$: Fe: +3 x 2 = +6, O: -2 x 3 = -6
