Center time trouble

I am having trouble with a large amount of students who are to completing the assigned activities during Center time.  These are review activities on IXL in both ELA and math.  This has led me to give unannounced extra credit to those students who have done what was asked of them.  I’ve awarded 5 points per completed assignment.  I am also struggling with getting completed homework turned in, which makes correcting and reviewing for end of level tests difficult.  I realize that kids are excited for school to be ending but we still have work that needs to be done and three more weeks to go.  Please check your child’s grades for any missing work.
Thanks so much,
Mrs. Shelton