We need to support kids at all ability levels. I grew up in the UK in the 80s and even then we had different learning materials - stretch activities for the fast finishers, catch-up help for the struggling kids.

Later on, we were placed in one of six classes based on our ability levels, and of course you could move up or down (though I don't know if anyone did).

It meant you didn't sit there bored and frustrated thinking, "Oh, FFS" while someone labours over the screamingly obvious answer. If you're not *learning* in class then you're wasting everyone's time: 'Matilda' does a good job of explaining that one.