Well, I have always thought that wizarding childern just attended muggle primary school. I mean, if Muggle-born wizards attend it, why shouldn't Pure-bloods? It isn't legal for childern under 11 years of age to use magic, or own a wand, so there shouldnt be any problem with them attending Muggle school. Also, children need to learn basic maths skills, and like you said, to read and write, seen as Muggle school teaches this, I think Wizards would attend too.
This is not based on anything other than my thoughts really... But I hope I helped
Russia xxxxx