Is the Jar Full?

Stephen Covey in his book, First Things First, shares the following story experienced by one of his associates:

I attended a seminar once where the instructor was lecturing on time. At one point, he said, "Okay, time for a quiz." He reached under the table and pulled out a wide-mouthed gallon jar. He set it on the table next to a platter with some fist-sized rocks on it. "How many of these rocks do you think we can get in the jar?" he asked.  

After we made our guess, he said, "Okay. Let's find out." He set one rock in the jar . . . then another . . . then another.  I don't remember how many he got in, but he got the jar full. Then he asked, "Is this jar full?"  Everyone looked at the rocks and said, "Yes." 

Then he said, "Ahhh" He reached under the table and pulled out a bucket of gravel. Then he dumped some gravel in and shook the jar and the gravel went in all the little spaces left by the big rocks. Then he grinned and said once more, "Is the jar full?"

  

By this time the class was on to him. "Probably not," we said.  "Good!" he replied. He reached under the table and brought out a bucket of sand. He started dumping the sand in and it went into all of the little spaces left by the rocks and the gravel. And the last is he put the water in it. Once more he looked and said, "Is this jar full?"  "No!" we roared.

"No," he said, "that's not really the point.

The point is this:

Put the Big Rocks in First

It mean that you must solve the biggest problem first, then u can solve smaller problem easier.