The truth is many people just don't "get" math. The concepts don't fit together, or the pace of the class is too fast. There isn't just one way to teach math that everyone will understand. Unfortunately, your teachers do not have the time to try to work to everyone's individual needs. Although they try their best, there are too many students and too short a time to work with everyone.
If you or your child is one of the people that just need that little extra something then consider tutoring. For a nominal price you can be presented the material in a way that works for you! I can focus on what techniques and strategies for learning suit you best and develop a plan to help you succeed!