What is the oxidation number of Mn in KMnO4​ and of S in Na2​S2​O3​?

Let the Ox.no. of Mn in KMnO4​ be x.
We know that, OX.no. of K=+1
Ox.no. of O=−2
So, Ox. no. K+ Ox. no. Mn + 4(Ox.no.O)=0
or +1+x+4(−2)=0
or +1+x−8=0
or x=+8−1=+7
Hence, Ox.no. of Mn in KMnO4​ is +7.
Similarly, for S in Na2​S2​O3​,
2(Ox.no.Na)+2(Ox.no.S)+3(OX.no.O)=0
2×(+1)+2x+3(−2)=0
x=+2
Hence, Ox. no. of S in Na2​S2​O3​=+2.