The question is now "how do we go from 6.0 to get back to 0.0006?"
The answer is "move the decimal point 4 spots to the left". This movement of "move 4 left" means the exponent is -4. The negative because we moved to the left. The 4 indicates how many spaces we moved.
So we get the scientific notation value of which is the same as because 6.0 simplifies to 6