My guess would be along the lines of what knute974 said. Wolf is doing the practice for the STAR test and he's a couple grades ahead in math and a bunch in language arts. It's really easy to see what EPGY hasn't gone over in awhile! He remembers as soon as we discuss it though, so I'm not really worried. I mean when you have a kid who is writing novels, basic stuff that was learned years ago isn't necessarily kept in the instant access area of the brain.