This is a redox reaction (and we will see why!), and we separate the reaction into individual oxidation reduction couples.......
And for each half equation, charge and mass are balanced ABSOLUTELY, as indeed they must be if we purport to represent chemical reality. I add them in such a way as to eliminate the electrons from the final equation, i.e.
And this is in fact balanced with respect to mass and charge. But we could add
And to make it even simpler, I could remove
i.e. a four electron reduction with respect to