I'm preparing for a maths interview lesson which has to support children's addition and subtraction skills. I've been told there is one SEN child in the class and normal classroom differentiation is appropriate. Do you think I can assume the children will be sitting in their ability groupings? Or would it be better to plan for a mixed ability activity? I have lots of ideas for the lesson, but the question of differentiation in a class you don't know.... does anybody have any tips?