Number of electrons transferred in each case when KMnO_4, acts as oxidizing agent and convert into MnO₂, Mn²⁺, Mn(OH)₃
and  MnO₄²⁻ are respectively

In KMnO₄ the O.N. of Mn is +7

 in MnO₄²⁻  +6

in MnO₂  +4 

in Mn₂​O₃   +3

 and in Mn²⁺ is +2.

 K$\stackrel{+7}{\mathrm{Mn}}$O₄$\to$$\stackrel{+2}{\mathrm{Mn}}$O₂  the number of electrons transfered =3

  K$\stackrel{+7}{\mathrm{Mn}}$O₄$\to$$\stackrel{+2}{\mathrm{Mn}}$   the number of electrons transfered =5

 K$\stackrel{+7}{\mathrm{Mn}}$O₄$\to$$\stackrel{+3}{\mathrm{Mn}}$(OH)₃ the number of electrons transfered = 4

 K$\stackrel{+7}{\mathrm{Mn}}$O₄$\to$ $\stackrel{+6}{\mathrm{Mn}}$O₄²⁻  the number of electrons transfered =1