We are using RS A with ds 4. He, too, has always counted objects previously, and was quite good at it. In RS A, they do quite a few activities with looking and knowing 1-3 objects, only adding in four and five objects after 1-3 objects are mastered (identified on sight). My son knows 1-3 on sight, and knows that 4 objects has no "middle" and five objects has a "middle", which is how he distinguishes these two higher numbers that he can't "see" as easily as 1-3. Any numbers above five require grouping for him to see, plus the Yellow is the Sun song.