Student A and B worksheets are perhaps the easiest way of adding real communication and fun controlled practice to classes with anywhere from four to sixty students. They can also be stimulating and useful in smaller classes, as long as you consider the issues below.
Pairwork activities with one student
Doing a task designed for two students but with the teacher taking one role is in some ways easier than having two students do it, as at least one person definitely understands what to do! However, there are possible issues.
With information-gap activities, the teacher usually already knows what’s on the student’s sheet and so that aspect of real communication is lost, along with any competitive element. The teacher pretending not to know everything with wrong guesses etc can work, but this illusion is lost if the student doesn’t understand something and so the teacher needs to look at the student’s page. You therefore need to set up such activities even more carefully than in group classes, perhaps even starting with a similar pair of mock Student A and B worksheets to demonstrate the activity with while the student looks at both.
The same problems can also be solved by using two of an activity that has multiple sheets such as something that was originally designed for mingling. Similarly, using worksheets with big lists helps make sure the teacher doesn’t have any advantage and that the teacher and student must really communicate to know which they are speaking about.
Pairwork activities with two students
Pairwork often works well in classes with two students, as the teacher can easily monitor if they are doing the activity correctly, walking behind each student to point at the relevant parts of their worksheet if necessary. However, there could be one or two different problems.
For some students, the selling point of a small class is that it gives them more time to talk to the teacher. Such students will need a lot of persuading to do pairwork while the teacher seems to be doing nothing, so you’ll need to really justify the activity and show that you are busy taking notes etc as they do so.
The opposite kind of student is one who would be fine doing a pairwork roleplay, game etc if they were hidden by the noise of a whole class doing it, but feels shy doing so with no background noise and doing so right in front of the teacher. You can get them used to doing so with less embarrassing activities like restaurant roleplays. The teacher can also show they are busy doing something else like filling in the register to make such students feel less self-conscious. In some situations, some background noise related to the situation or some quiet music might also help.
Pairwork activities with three students
The issues above are less likely with three students, but still possible. In addition, you have a weird number of students for pairwork activities. The most obvious solution is for the teacher to become Student B in one pair, but you may need to think about students being shy about working with the teacher, other students resenting not having that opportunity, and/ or it being difficult to monitor the other pair at the same time. It is therefore often preferable to put two students together on one side of the activity, e.g. one student with the Student A error correction worksheet, and the other two sharing the Student B one. If the activity has lots of short interactions, it could also be circled around the class (roleplay 1 with Students A and B, roleplay 2 with students B and C, etc).