The standard form is also known as the Scientific Notation
So to find the standard form for 3.050904 we need to start counting from 4 until we reach the zero. So let's count :)
I got 6 numbers (but don't count number 3)
Now since the virgule is in front of the 6 number we will have ^-6
Like that : 3050904*10^-6
Why do we have -6 instead of 6 ? well the reason is because we're going on the left side. Because we start counting from right(4) until we reach the left side(0)
I hope that's help and please if you have any suggestion let me know :)