This is the 1st most frequent Swedish word.
i
"In."
In this sentence, 'i' is used as a preposition meaning 'in', indicating the location where the subject resides.
Jag bor i Sverige.
I live in Sweden.
Here, 'i' serves as a preposition meaning 'inside', specifying the position of the book relative to the bag.
Boken ligger i väskan.
The book is in the bag.
In this context, 'i' is used metaphorically to express participation or involvement in an institution, in this case, school.