To him this is a very novel concept, albeit one that we have been attempting to explain to him the last couple of years.
Still, I'm so happy he's figured these two things out, it's doing wonders for his motivation to learn and ability to focus. I can now see real daily progress in each of our study session. He is beginning to retain new letters after a couple of days of study instead of several weeks. The same is happening with his sight words. I also saw a break though with counting. He used to 15 every time, even after constant reminders. A couple of weeks ago he mastered counting to 20 and is well on his way to 50.
He's also remembering simple words in his books from school. When we began reading them I tried explaining to him that the words were the same on every page but had a different action, like "We go to school, we go to the park, we go to bed," and every time we turned the page, even though "we go to" was exactly the same, he could not remember the words. Finally those days are over and he is reading those little books on his own! It's incredible to see his progress and witness him learn to read. Yeah, you could say I'm pretty proud of him. :)