That would be very useful but I don't think the current style of school practice is doing it. "Sustaining interest" is missing. Both the textbook or class are a

That would be very useful but I don't think the current style of school practice is doing it. "Sustaining interest" is missing. Both the textbook or class are abstract (they have enough trouble describing a math concept and don't spend much or any time showing where that concept is headed for example - what it will later be useful for). And the exercises are narrow: they make no reference to real world problems. Granted that created exercises grounded in real world problems is far more time consuming than isolated questions. Would still be more useful.