If you check Infinite Campus for your student's grades you will notice the grade book has been broken down in to two categories; formative and summative.
Formative assignments are NOT counted towards the calculation of a students grade. Formative assignments are given multiple times throughout a unit to see where a student stands at that point in time, relative the learning standards. Some of these assignments will simply be marked as "turned in" so that you can see your student is participating in class activities whereas other assignments will have a score assigned to them. By posting the score from these assignments in Infinite Campus students, parents, and teachers are able to view a student's progress towards mastering the learning standard(s). They are merely a form of information for stakeholders to show a student's area of strength, weakness, and progress over the course of a unit.
Summative assignments ARE graded and counted towards the calculation of a student's grade. These assignments are given to assess the student's overall learning of a standard(s) prior to moving on to the next topic.