Which number is written in scientific notation?

A : 4.5 * 10^-3 B : 14.5 * 10^2 C : 0.78 * 10^-6 D : 5.7 * 4^8

I believe the answer is 14.5 * 10^2 (b)

A : 4.5 * 10^-3

Step-by-step explanation:

Scientific notation is a way to write numbers which are to large or to short, for example the diameter of the Earth, or the diameter of the nucleus of an atom. It's important to know that this notation is based on power with a base of 10.

So, to write number in scientific notations, there are some rules or convetions. First of all, the power must be based on 10. Second, the whole number part of the scientific notation must be between 0 and 10, where 0 and 10 are not included.

Now, having said that, you can observe that choice A is the one that completes this rules, because it has a power based on 10, and its whole part is between 0 and 9.

Therefore, the right answer is A.