I thought I would explain my rotations a little more. I am very fortunate to choose my math block schedule. The only real interruption that I had to account for was a math pull out group for struggling students. This happened last year 30 minutes into my math block so the goal here was to have whole group and my low group for math stations first. This way the two pull out students would have necessary instruction before leaving. When those two students returned they were able to work together at a math station (although they sometimes missed out on a station entirely if the math teacher who pulled them out kept them too long).
So I have four main groups but really only see three a day for 20 minutes. I alternate when I see my two higher groups. Some days I would see both groups for only about 10 minutes to check in and see how they were doing on their independent work and most days I would meet with the Med. High group M, W, F and the High group on Thursday and Friday.
I am really wishing I had taken pictures of everything before I packed up my room. I don't have a picture of my rotation board but I will post a picture of what it basically looked like. I had everything on magnets and on a large magnetic board (but, I am going to use that for something else next year so I may use a pocket chart). I really like having everything on magnets because I could change my groups and stations as needed. You will see in the picture that I used the magnetic business cards from VistaPrint and wrote on them with a sharpie. Where you see the arrows that is to let you know who my station groups of two were. The actual display didn't have arrows they just knew the name under or above theirs was their partner. The actual display also does not have the words low/med./high on them (that was just for explanation). My board was spaced out so you could tell just by looking. The choice cards use Thistle Girl Graphics and since I am just a member and don't have the license to share them I can't post my printable. I may have to invest in that so I can share some of my things.
One thing that I didn't do was assign particular math stations to specific groups of students. I am thinking that I will work on this for next year so that I can differentiate more. The only thing I did do with differentiation was having a few specific math stations for my high group that only that group could complete. I will be interested to learn more about differentiating my math stations.
I formed my math groups at the beginning of each of my 8 math units (as dictated by my district). I definitely had some students that were low in place value and high in geometry. During that unit my groups stayed the same unless I saw great growth or loss and felt individual changes needed to be made.
I don't use a specific timer for stations. I do sound a chime as a warning to clean up and then again when it is time to switch. The reason I did this was that I sometimes felt like my low group may have needed an extra 5 minutes meeting with me or another group really needed 5 less minutes, etc. I like being able to determine when students can leave my group. I did try to keep my rotations to 20 minutes.