This is a well thought out concept that is put together in a STAIR for students to guide themselves through. This is a difficult concept and while introduced in 3rd grade, would be a great lesson to use with almost any grade. I may have learned a few things myself! I did have difficulty viewing some of the videos. I am not sure if it was my computer that wasn't working or the video itself. I do like the feedback it gave when students answered correctly or incorrectly, the simple sound effects make a difference to 3rd graders. I think a few of the questions were wordy and some may have trouble with them. But I think they were similar to what studnets may see on standardized tests so it may be good practice for them. There were many visual opportunities to hear and see the concept being taught and was backed by immediate quetions and feedback which is a great advantage to using a STAIR. Overall, I highly recommend this lesson and look forward to using in my classroom this upcoming year. I think it will be a great lesson to display on the smartboard in small groups to allow for discussion as well as using indivudally.