This is a very handy organizer and visual to use when doing centers in your classroom. I got the idea from my mentoring teacher and brought it to my classroom last year. Since ELA is such a complex class and often concentrated to fit the 90 minute time frame, I break my centers up into 3 days. That allows the students to get more time in each center. I spend the last 30 minutes of class doing 2 rounds of 15 minutes, but you can set the timer as you please.
I am known as "The Crazy Cat La