We're working our way through elementary school, app list style. This week's feature is my opinion on the must-have iPad apps in a classroom or at home for second grade students. But don't forget about the Kindergarten Top 10 list and the First Grade Top 10 list. Many of the apps on the first grade list are still very appropriate for second grade students. And keep watching for the third grade list, since many second grade students are ready for the challenges that list will bring.