Answer/ explanation :
The oxidation number of N2O3
The oxidation number of O = -2
The oxidation number of N = x
Since there are 2 moles of N
And 3 moles of O
Therefore,
2 * x + (-2 * 3) = 0
2x + (-6) = 0
+ * - = -
2x - 6 = 0
Find x, divide both sides by 2
2x = 6
2x / 2= 6/2
2 cancels 2
x = +3
The negative or positive sign is very important, so it must be added.