Middle School (or junior high) is not reteaching children what they have already learned. Middle school can be an important time, a "transition" period between childhood and the teenage years. Middle school lays the foundation for years to come, and without it students would be unprepared for high school and college.
Children in middle school are being taught addition, subtraction, multiplication and division. Then they get taught fractions and decimals. I believe that they should learn and be challenged as to create a better learning environment. Middle schoolers should be challenged with harder things to learn.