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I'm taking physics this year and the first thing my teacher says to us is how to round, or to be more precise, how to round when the last digit is 5.
I firmly disagree with this statement. Is this just some querky physicists thing though? or is it just my teacher...Quote:
Originally Posted by My Physics Teacher
One thing I know, because I am a teacher...You'd better do what your teacher says, because as far as the class is concerned, he/she is God! :)Quote:
Originally Posted by Quick
As far as the rounding is concerned, there are several "standard" ways of rounding. They are used in Math, but not as much because Math classes generally tend to use exact numbers, not rounded.
I have heard of the rounding method you describe and it probably works as well as any other I've heard of. The one I generally subscribe to is a bit simpler:
This sounds like it's perfectly reasonable, but there is a hidden problem: significant digits. You probably won't run into these until High School. The problem is there is generally some uncertainty in the last digit of any measured number. When in doubt, the last digit has an uncertainty plus/minus 1. So the number 10.5 is reallyQuote:
If the number ends in a 5 exactly then round down. If there are any numbers after the 5 then round up.
. How do you round this using my method? You can't. (However we can just drop the last digit and say the number is
, so we don't really have to worry about it, either.)
Basically you'll see a lot of arbitrary definitions used in your Physics classes. You'll find that the rounding scheme is going to be the least of these, so don't worry about it too much. :p
-Dan
Why would you round down? 5 should always go up.
Although I won't try debating with my teacher, I only do that to teachers I feel will give up :D
i've always used this method:Quote:
Originally Posted by Quick
it may not be right but it has always worked for me:DQuote:
"if the digit after the digit you are rounding to is <=5 then round up, if it is less then 5 then round down..."
dan
Hello, Quick!
I was taught that even-odd routine for "rounding on 5" many years ago.
Since 5 is exactly halfway, the rounding is evidently arbitrary.
So to be "fair", someone invented that scheme: Odd-Add.
Since then, however, I have "rounded up on 5."
Here is my reasoning . . .
The digit can be any of ten possible digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9.
For half of them {0, 1, 2, 3, 4}, we round down.
For half of them {5, 6, 7, 8, 9}, we round up.
To me, that is "fair".
Though I deeply feel with you on this statement, I DO in fact debate with my teachers. I wouldn't recommend doing so until late Undergrad, though. :) I've been quite happy to leave a number of my teachers behind, though, Godlike though they may have been in their classrooms.Quote:
Originally Posted by Quick
-Dan