really confused with oxidations reducations reactions with multiple elements

[knooch]

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Mn goes from +4 (in MnO2) to +2 (in MnCl2), so it's reduced, easy.
O goes from -1 (in H2O2) to 0 (in O2), so H2O2 is oxidized, BUT
why wouldn't you say O goes from -1 (in H2O2) to -2 (in H2O) than H2O2 would be reduced.

H2O2 is oxidized according to the answers, but I don't understand why you would use the oxygen in O2 as a comparison instead of the oxygen in H2O.
Were we expected to know the oxygen in H2O2 goes to O2 and the oxygen in H2O comes from MnO2?

 

[t5Nitro]

In acidic solutions H2O2 is a much better oxidizing agent than it is a reducing agent.

 

[sps27]

I think you take the highest number for the element on the right and left hand side. So on the left hand side it is -1 for oxygen and on the right hand side, it is 0 for oxygen. It really does not matter how the element gets split apart in different compounds. Now we know that MN has got reduced. So something must have got oxidized so we look at oxygen and it went up from -1 to 0, so we say, H2O2 got oxidized from -1 to 0.