Question

HELP MEEEEEEEEEEEEE PLZZZZZZZZZZZZ

Answer 1

Let's say we wanted to subtract these measurements.

We can do the calculation exactly:

45.367 - 43.43 = 1.937

But let's take the idea that measurements were rounded to that last decimal place.  

So 45.367 might be as small as 45.3665 or as large as 45.3675.

Similarly 43.43 might be as small as 43.425 or as large as 43.435.

So our difference may be as large as

45.3675 - 43.425 = 1.9425

or as small as

45.3665 - 43.435 = 1.9315

If we express our answer as  1.937 that means we're saying the true measurement is between 1.9365 and 1.9375.  Since we determined our true measurement was between 1.9313 and 1.9425, the measurement with more digits overestimates the accuracy.

The usual rule is to when we add or subtract to express the result to the accuracy our least accurate measurement, here two decimal places.

We get 1.94 so an imputed range between 1.935 and 1.945.  Our actual range doesn't exactly line up with this, so we're only approximating the error, but the approximate inaccuracy is maintained.

Answer 2

Actually, that person is wrong. He/she didn't explain what the statement means very clearly. She/he also used different numbers (She/he did use 45.367 and 43.43) other than the numbers mentioned in this question. If you used that answer, you would get points off so do't use it! Use mine! I turned it in for a math journal in K12 and got 100%! it is not copied! If you think it is, search it up on a plagiarism website. Here:

The statement, “When you calculate with measurements, your answer shouldn’t be any more precise than the least precise measurement.”, means that whatever number is the least precise in the problem, is basically going to turn out to be the most precise because all of the other numbers will have to be rounded to the least precise number (in this case, the hundredths place) so that it has the same place value as the least precise measurement in the problem. That means that 45.367 will have to be rounded into 45.36 because 43.43 ends in the hundredths place.