It sounds as though he has a great deal of anxiety about learning.  Could he be afraid of failure?  He is at such a tender age to have developed these feelings, but I've seen it many times with older children who have experienced years of frustration over learning and are afraid to try. The best remedy I have found for this is success.  Success breeds more success.  Children need to have confidence in themselves to be able to relax enough to surmount a new obstacle.  As a special ed. teacher, I have the time to coax a student into trying and this sounds like what you are successfully doing at home with him. It is quite understandable that a classroom teacher cannot put this much focus on one child.  However, could you get a lesson your child's teacher will present before it is given to the class, teach it to your child, and with a little help on his teacher's part, let your child be one-up on all the answers?  This may be the success to launch his confidence into his expecting success instead of failure.  Perhaps then his anxiety will diminish and he will be sufficiently relaxed to learn.