Determine the oxidation number of the element that is underlined within the compound. li2 sio3
+2
+4
-2
-4

You forgot to underline the element.

I can give you the oxidation number for the three elements

Li: +1 (this is the only oxidation number for this element)

O: -2 (this is the only oxidation number when it is not forming a peroxide)

Then: Oxidation number of Si is calculated from X +2(+1) + 3(-2) = 0

x +2 - 6  = 0

x = 6 - 2

x = 4

The oxidation number of Si is +4.