Smart Work ???

Smart work, a word used by majority of people especially it is used in education related fields. What does that mean ?? and how is it different from Hard Work?

In simple words, hard work means that you are doing something with full dedication but you don't actually why and what you are doing, whereas smart work includes working 
with full presence and understanding.
Let's say you need to complete certain topics for a test or presentation in a short period of time, Hard work here means that you start reading that chapter from beginning and continuously doing it with full dedication, you work whole day and night to complete the task, is that really beneficial ?? Rather here we could do smart work, we could analyze the topics given to us, and find out the most important topic for the required task, let's say there were 3 such subtopics which didn't have that importance for the task but one who did hard work would have wasted time to learn that portion also, because he was doing as it is, without really understanding what he is doing.
This is a gist of what Smart work means. We can find several aspects especially in terms of our preparation of our main target so as to make our work easier and systematic. Like we can look into methodology of Forgetting Curve, which if unknown can give several problems in student's life.
Forgetting Curve is something which can give answers to most of the questions that why all teachers and guides insist us to revise topic covered timely, as we move ahead in time, our retention capacity of that topic reduces exponentially, thus timely revision can help us break the forgetting curve and make us retain things for much longer time.