I have been fortunate enough to teach a more accelerated math class to third graders the past few years. Since most of my students have already mastered addition concepts, I found joy in creating activities that challenged their brains, but still fit in with 3rd grade standards. I used this activity PRIOR to reading One Grain of Rice OR The King's Chessboard (they are the same story). The students LOVED trying to figure out which option was better and got even MORE excited when they started to see the power of doubling. They were practicing addition skills in a BIG way without even knowing it. This is just a simple recording sheet, but I found it so helpful in helping them organize their work. I could also use it for a classwork grade and send home for the parents to see what we were working on in class.