I hav a few questions on 'scientific notation':

a) there isNOnumber in scientific notation that is negative, am i right?

b) 3x10^2 and 3.0x10^2. Which one is in scientific notation? Both correct? Can I ignore the decimal point?

c) 1.2 and 1.2x10^0. Which one is in scientific notation? Both?

d) 4.3x10 and 4.3x10^1. Which one is in scientific notation? Can I ignore the power of 10 if the power is 1?

Can anyone provide me the rules of writing a number in scientific notation?

Thanks a lot!!!!!

p/s: URGENT