In DS1's school the teacher differentiates the work. From what DS1 tells me, they all start with an intro/explanation of the topic they are going to do that day (last week it was things like addition, subtraction and this week they are doing times tables), and then they all get on with their work.
DS1 gets to practice the same concept but doing addition and subtraction of two and three digit numbers. And when they were doing multiplication, the teacher tested him on all tables from 1 to 10, and as he had a bit of trouble with x9, that's the one she told him to practice. Today he was tested on x11 and x12, and she told him to practice the x12.
As far as I know, the Y2 usual times tables are x2, x5, x10 (those are the ones the other children were practising).
So, depending on the the school and teacher, work can be differentiated taking into consideration the student as an individual. I think that is how it should be.
Every time I read threads like this, they make me realise how lucky we have been with the school/teachers DS1 has had so far, as it doesn't seem to be the rule but rather the exception.