How to work out number of electrons transferred in a reaction? good chemist required

How many electrons are transferred in the following reaction? The equation would have to be balanced before answering I assume?

SO32-(aq) + MnO4-(aq) → SO42-(aq) + Mn2+(aq)

Thanks for the help!

Set up the two half-equations to begin with, giving:

[1] (SO3)2- + H2O ---> (SO4)2- + 2H+ + 2e
[2] (MnO4)- + 8H+ + 5e ---> Mn2+ + 4H2O

Before adding [1] has to be multiplied by 5, and [2] by 2 to balance the electrons. After cancelling H2O and H+ this gives...
2(MnO4)- + 5(SO3)2- + 6H+ ---> 2Mn2+ + 5(SO4)2- + 3H2O