A student can be expelled from school for either the end of the school year or forever from that school district.
Being suspended the student is usually suspended from school for 10 days to a month but if a student gets expelled it usually means that the expelled student is banned from going back to that school for the rest of the year or in some places the student may be permanently expelled from that school and can never return to that school.
Still the student must attend school even after being expelled and when the student is expelled they will need to go to another school in another school district or they will need to be home schooled.
Just because a student is expelled doesn't mean they can cease doing school work or going to school because they still are required by law to attend school in another school district or do home schooling.