## amusemuse 2 years ago So, my textbook taught me in one of the steps add the exponents. For example: 1.5 x 10^1 * 10^-7 1.5 x 10^-6 But, a problem of mine I have completed just got me confused because the answer I got isn't any of the answers available. It's a multiple choice. Here is my problem: (2.5 x 10^-9) (1.5 x 10^3) = (2.5 * 1.5) (10^-9 * 10^3) = 3.75 * 10^-6 = 3.75 x 10^1 * 10^-6 = 3.75 x 10^-5 Did I do something wrong? If so can someone explain this to me?

1. tomo

why did you add a 10^1 in the 3rd line of your equations.

2. JayDS

= 3.75 * 10^-6 (this is without what @tomo said, u don't need the extra 10^1 which you added)

3. kirbykirby

Ya you can't introduce the extra 10^1... (unless you did it to both sides of the equality)

4. kirbykirby

However, it would be correct if you wrote = 3.75 x 10^1 * 10^-7

5. kirbykirby

Here you are breaking up the exponents. Like what your book example did (But this is not necessary to write because it is a longer expression)

6. amusemuse

I addede the 10^1 because that's what my textbook said to do. So, I don't need to do that?

7. kirbykirby

The book didn't "add" the extra 10^1.. if you look carefully; the first is exponent ^-6, then they write ^1 and ^-7 (NOT ^-6)

8. kirbykirby

You have ^-6 and you introduce ^1 and wrote ^1 and ^-6

9. kirbykirby

The point of the example was to show you how to add the exponents together.

10. amusemuse

Oh alright. I got it. Thank you so much!!

11. kirbykirby

np =)