Oxidation number approximately I argued with my lecturer when he is saying that during the calculation of oxidation number, and your answer give you like 3.46 you can approximate it to whole number, I know tell him NO that if the answer is in decimal that means your calculations is wrong, he now tell me to go and research on my thought.
So please can anyone help me out
For complex or non stoichiometric ( many metal oxides ) compounds, it makes sense to calculate the average oxidation number that can be a rational number.
This can be useful if we are to enumerate chemical reactions with non-stoichiometric metal oxides, or if just a summary elemental composition is known, like hydrocarbon mixtures.
Oxidation numbers of particular atoms are integer numbers, with exceptions when   extra electrons ( or theirs deficit ) are shared among different number of atoms. The particular example of this are superoxides $\ce{M^{I}O2}$.