Good / Smart
astute - Ability to understand things quickly and clearly, and to use the knowledge well
From a very early age, Gail instinctively knew everything about business, and and after college she proved to be an astute business woman, and became a millionaire before the age of 30.
shortcut - A simplified way to complete a task, often by bypassing steps in a process; or a path or way that reduces the usual time or distance required to reach a destination.

He surprised the teacher by figuring out a shortcut method of solving the math problem that saved time compared to the method she had taught before.