How is this number expressed In scientific notation?

6x10^-4

Step-by-step explanation:

Move the decimal so there is one non-zero digit to the left of the decimal point. The number of decimal places you move will be the exponent on the  

10

If the decimal is being moved to the right, the exponent will be negative. If the decimal is being moved to the left, the exponent will be positive.

6x10-4

Step-by-step explanation:

There is four 0 so its negative 4 by 10