I know there are 4.5*10^-9 seconds in 4.5 nanoseconds, but when I enter it into my TI-30xIIs, I get 4.5*10^-10. I enter it as 4.5 * (1/10^9) in my calculator ... what am I doing wrong?

You are not using properly the function exponential in your calculator

Explanation:

When a number is too big or too small we use scientific notation. This is a number between 1 a 10 multiplied by a power of 10.

When you are writing 4.5*10^-9 you are actually writing 0.0000000045 in scientific notation.

When you enter this in the calculator you have to use the function EXP after the first two numbers.

Steps: 1) Enter 4.5

2) Enter EXP

3) Enter minus (-)

4) Enter 9