First of all, as a former teacher, thank you for being an involved parent who strives to help your child at home. That goes a very long way and says a lot about you as a parent and person. Second of all, I'm so sorry your son is struggling. I hated math growing up. Gosh, I actually remember telling my parents I was going to drop out of school in third grade because I couldn't grasp long division. Anyway, I do understand what your son is going through. I also remember how frustrating it was trying to have my mother (who also had taught math) try and explain things to me at home. Sometimes, parents just aren't the best teachers for their children. Have you considered getting your son some extra help? The fact that he is able to get it when test time rolls around lets you know that he is on grade level and there is likely not any sort of disability there. He's just struggling to grasp it at the point it is being taught and there is absolutely no shame in that. You could go to a tutoring place like Mathnasium or Sylvan, or you could look into hiring a tutor. I know plenty of SAHMs who were once math teachers and now tutor in the evenings. And, of course, your son's teacher is also a resource if you think he/she would be able to help get through to your son with just a bit more time. Personally, I was always a fan of a tutor who is not the teacher just because he or she can present the information in a different way that perhaps your son hasn't been exposed to. No matter what you decide, try to take a deep breath and just relax. You are doing a great job just by being involved.