Thread: Runway ID
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  #8  
Old October 18th 05, 12:27 AM
Mike W.
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Default Runway ID


"Jose" wrote in message
...
If you have 0.245, it is 0.24 rounded to hundreths. How is that '5 goes

up?'

If you actually have 0.245, it is 0.25 rounded to hundredths. However,
if you actually have 0.2445, you do NOT have .0245 but a hair less than
that. In that case, you don't =have= a five to "go up".

If you took a big pile of numbers, rounded them all up, added them,
you would have a value that was way off of the true value of the sum.


True. But you don't round them all =up=. You round them all (to the
nearest). Only the ones that are ...5 and up get rounded up. The
others get truncated. Including ...0 which gets its zero truncated
(leaving the number unchanged).

0.247 - 0.25 0.255 - 0.26 is that what you mean? That's exactly

what I
stated.


This is correct rounding, but it is it what George stated. He stated
"round 1/2 to the EVEN number.", which would imply .245 - .26 which is
not true. What =is= true is
.245 - .25
.255 - .26
.265 - .27


You don't round them all up? That is exactly what you are doing in your
example above.

If the digit before the last is even, and the last is five, you round DOWN
(0.245 - 0.24) If the digit before the last is odd and the last is five,
you round up. (0.255 - 0.26).

Bear with me and look at these two examples. The one on the left is a
summation of the example you have above. The one on the right is 'my' way. I
am just summing the original values and the rounded values at the bottom.

.245 - .25 .245 - .24
.255 - .26 .255 - .26
+ .265 - .27 + .265 - .26
------------ ------------
.765 - .78 .765 - .76

You can see where this will get you very quickly if you use the way you
propose.

Of course our original discussion started off regarding rounding a single
number and doing nothing with it, this is just a point of interest.



This is not "rounding 1/2 to the even number".

Jose
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