Adding a little to Jason's response, if you want the values in N16, N24, &
N31 to be just what they appear to be, apply the Round() function to them,
rounding them to 3 decimal places.

If the values were in contiguous cells you could , use an array formula,
committed by pressing Ctrl-Shift-Enter:

=SUM(ROUND(A1:A3,3))

"Chipster" wrote:

Formula in cell N34 adds N16 (11.1%), N24 (44.4%), and N31 (44.4%). The
total displayed in N34 is 100.0%, should be 99.9%.