Have you ever wanted to have a chance to turn the wheels of time back and have a second chance on something?  I have made plenty of mistakes in my life.  I continue to make mistakes every day.  What is most important is that we learn from our mistakes.  Well, in school, learning is our goal.  In my class I do give my students a chance to redo an assignment and even a test or quiz.  When students do not do well on something graded, I pull them during recess, intervention, or class time to reteach the skill in a smaller group.  I try to make sure they understand all the mistakes they made.  They then get a comparable assignment to redo.  If they still are not successful, I will work with them one on one or in smaller groups and look for other resources to use with them.  This will help improve their grade and their skills.