SUM Formula - Not Totaling Values with Decimals

[ahigginbotham]

I have four (4) columns that are number data fields titled {Trip 1 Miles}, {Trip 2 Miles}, {Trip 3 Miles}, and {Trip 4 Miles}. The settings to the number data fields include decimal places and a screenshot of the settings are attached.

Column five (5) is titled {Total Miles Traveled} which is a formula data field that SUMS the total of the number data fields listed above. 

THE PROBLEM TO SOLVE: I am unable to get the formula in {Total Miles Traveled} to include decimal points in the SUM total. A screenshot is attached. The formula is totaling [26.70 + 26.70 + 9.10 + 9.10] and is rounding the answer to [72] instead of the desired answer with decimal points as [71.60].

[ahigginbotham]

Current Formula that Does NOT Return Decimal Places as Desired

[Alexey_Gusev]

Hi,
solution is here (I think there is nothing to add):

[Alexey_Gusev]

no,

I think, this worth to be added, and maybe save time for somebody, 

you are using SUM in a strange way
SUM(A,B,C)  is the same(almost)  as  A+B+C
In your formula SUM(A+B+C) works just because SUM(X)=X

The difference is when any of fields is NaN
A+B+NaN=NaN
SUM(A,B,NaN)=SUM(A,B)
I suppose it works with #ERROR too, but i'm not sure