We have started investigations this year and didn't realize until the end of the year that we probably did the units out of order. Is there a particular order? It seems odd to be doing addition and subtraction after Arrays - the other problem we have encountered as a grade level is the "lost in the text" teacher prep notes. Being responsible for ALL subject areas in a self-contained fourth grade classroom and meeting TEXAS standards for writing, I really don't want to have to research every lesson before teaching it - The kids love it expecially the fractions unit but it isn't very teacher friendly. I have committed to making it work well but I would at least like to know in which order I should be teaching it. We are all fortunate to have adequate manipulatives in each classroom.