Flexible grouping is an easy way to differentiate work session activities. One way is by providing students three choices of grouping, you are not only differentiating, you are also giving students ownership in their education. It will help both interpersonal and intrapersonal learners. The three choices should be to work by themselves, with a partner or with a group. If these choices are given to the students the day before the activity is to be done then the teacher can use their choices to create workable pairs or groups. Depending on the project or activity the teacher may group by ability level and work more closely with the lower level or the teacher could use mixed ability grouping and allow the students with a higher ability level to guide or teach the students who struggle. It also allows teachers to make the amount of copies needed. Flexible grouping can change with every project or multiple times per lesson.
http://www.teacherspayteachers.com/Store/Kasha-Mastrodomenico/Category/Activity-Templates-and-Rubrics helps middle school social studies teachers differentiate instruction, Check it out!