Hello!
Standard notation is a scientific formula written in standard form. For example, 10^3 is scientific form, while 1,000 is that in standard form.
For this problem, we have 3.05(10^-3). When we are working with tens, we move the decimal to the left or the right a certain amount of times. Since we have a negative exponent we will move it to the left. We will do so three times.
This leaves us with the standard notation being 0.00305.
I hope this helps!