How can teachers design instructions, activities and assignments to be suitable for mixed abilities classes?

The best way to provide such variety to set of students of a class would be via the Google+. You could design different instructions, activities, and assignments having observed and recorded the abilities of the students. The tasks could be shared with students having set up the google classroom. Your education system should have facilitated teachers and students and trained to use Google classrooms.  

In an ordinary class situation; the teacher could categorize their students according to their ability and prepare lessons and activities. Assign activities to groups that would need no verbal instruction and attend to others closely in a mixed ability class. It’s about tasks and time kind of plan that would help the teacher to facilitate all students without students running out of activities during the class time.

For activities: Variation in groups is mandatory so as to give slow learners the chance to learn from upper levels. This can create competition and challenge between groups as well. 

For assigments: They should be multi-leveled to give more than an option suitable for all levels and abilities. The slow learner would feel free to select any assignment without being shy or stressed if the task was designed for advanced leaners.

hello dear

by dividing categories by age from here we can communicate information to students

thank charbel hanna

Simply by addressing certain levels of students with taska which correspond their level of mastering the language. Or any other subject. Thus, stronger students get more challenging tasks whilst weaker can do easier assignments