We are only on lesson 34 and I have had to search this forum several times just to try to figure out what we are supposed to be doing on a lesson or how I am supposed to explain something to my child (without using a formula. For example, worksheet 31 has arrays with some of the little squares cross hatched. No explanation why. Not even in the teacher's manual. Maybe this was explained on another level? If it was it would be helpful to have something saying "see level x lesson x". Lesson 26 was especially frustrating not only because of the lack of explanation of how to figure the problems out, but because some of the problems required counting states on a map, but the answer key did not give the # of states used. (For example,questions 20 and 21).
That particular lesson has been a struggle for many parents. In fact, RS has looked into that lesson and has revamped it for future releases. The point of the lesson, though, is to calculate percentage based on 50 states. That being said, if you don't come up with the exact percentage that the answer key has (as happened in my family every time we went through the lesson) that is ok - as long as they are getting the correct percentage from the states they have calculated.
Again, this lesson in the next release will be a little easier to use. Until then, feel free to post here or email me directly. I am happy to help you when I can!