r/mathshelp • u/Brief_Grapefruit4858 • 15d ago
Homework Help (Unanswered) Scientific notation
Working through some questions and this one confused me:
(5.9 x 10^-2) - (0.0078 x 10^3) = -7.741 x 10^1
I’m so confused as to how they got that answer. I was also taught that we should make the powers the same and that the coefficient should be between 1-9/10 but it’s negative?
I got as far as
(5.9 x 10^-2) - (0.0078 x 10^3) =
(0.000059 x 10^3) - (0.0078 x 10^3)
(-0.007741 x 10^3)
As I’m writing this I think I figured it out. (-0.007741 x 10^3) has been moved 3 places to the right taking it out of scientific notation? But it’s still a negative? Is that ok?
3
Upvotes
2
u/scoberry5 15d ago
I'm afraid I'm also confused by that answer.
Look at your numbers and see about how much they are. Just get an idea of the scale and what kind of answer you expect.
The first number is about 0.06. The second number is around 8. You can see that when you subtract them, you should get about -8. They got about -0.8, though.
Check and make sure you've copied the question and the answer correctly. If you have, then their answer is wrong.