Once submitted, a student cannot go back and retry problems until their teacher deletes progress on the assignment. If a teacher wishes to allow a student to modify their work, they can choose to delete a student's progress for a given assignment by clicking on the triple dot next to the student’s name in the Detailed Report section of the Assignment Report. “Delete Student Progress” will clear out all of the student’s data and allow them to redo the assignment using the original assignment link in Google Classroom or Canvas.
Warning - The student’s work cannot be recovered after deleting progress.