You would probably lose a couple decimals because a long train of decimals makes numbers more difficult to read. If you don't cut those off, there's no difference at all. It would be easier to express it in billions though. If you do end up rounding down and losing some decimals, I'm sure the government would thank you.
A number such as this would not normally be expressed in scientific notation.
This number would be rounded to 600,000 and the expressed in scientific notation as: 6.0*105
It would not normally be expressed in scientific notation but it is: 7.417717*10^5
3.7*101 Normally a small number like this would not have to be expressed in scientific notation
It would not normally be expressed in scientific notation but if so: 4.003*10^0
It is: 8.345*10^0 (Although this is not a number that would usually be expressed in scientific notation.)
5*106.
Such a number would be rounded to 30,000,000,000 and then expressed in scientific notation as 3.0*1010
A large number like this would be rounded to 30,000,000,000 and then expressed in scientific notation as: 3.0*1010
0.00069 expressed in scientific notation would be 6.9 x 10^-4.
3.844 * 108
It would be 8.645 x 105