Question

The oxidation numbers for each element in the compound Ag2SO3 are: (Enter numbers ONLY in the format +1 or -1; no spaces.)

Ag

S

O

for Ag i got +4
for S i got -2 and same for O

The oxidation numbers for each element in the compound NaClO4 are: (Enter numbers ONLY in the format +1 or -1; no spaces.)

Na

Cl

O

for Na i got +1 for Cl +7 and for O -2

Can any one verify these.

Answer 1

S is +4 and not -2
O is -2, correct.
BUT Ag is +1. Remember a compound is zero; therefore, 3 O at -2 each is -6, S is +4, which makes 2Ag +2 or +1 each.

You are on the money for NaClO4.
Na is +1
Cl is +7
Each O is -2.
Here is a good site if you need the rules.
http://www.chemteam.info/Redox/Redox-Rules.html