This sounds a lot like my DS. He's also 4, in kindergarten, reads at at least the 5th grade level, spells around a 2nd grade level and is around a 1st or 2nd grade level in math. Each student in my son's class receives one-on-one reading instruction with the teacher each day, and since he's already a fluent reader, his teacher uses that time to work on his spelling and writing, where he's much weaker. She has told us, "I'm not doing any reading instruction with him. He knows how to read." Instead, she asks him to read some short piece written at a 4th or 5th grade level and then gives him open-ended comprehension questions, which he has to answer in writing in full sentences. As I wrote on another recent post, my son is very emotional and a perfectionist, so the writing has involved no small amount of frustration and crying, but his teacher has been great about working him through it, and he's now writing/spelling voluntarily at home and is MUCH more comfortable with making mistakes than he was before school started. So, to the extent that focusing on a weakness has made things challenging and forced my son to cope with making mistakes, we're very happy that his teacher has gone this route.