Ammonium nitrite = NH4NO2
NH4+: Let the oxidation number of Nitrogen = x
x + 4 = 1 implies x = 1 - 4
x = -3
NO2−: x - 4 = -1
x = -1 + 4 implies x = +3.
The oxidation numbers for Nitrogen in Ammonium Nitrite = -3, +3.
