It's worth pointing out that different students are different people; each person has their unique background and knowledge when they first arrive in a classroom. If you've got a student who's struggling with < versus > they're going to have a real hard time with further math if you don't provide some support for them (and even then they'll still have a hard time, you'll just be helping them - it'll be similar to someone spotting you while you do bench presses near the limit of what you can handle).

There is no "best explanation, best worksheet" any more than there's a "best shoe size, best cut/style of pants".

Hire good teachers who care about their students, and let them figure out how to best address the needs of their students in that particular classroom.