In addition to what kcott wrote, there are Math::Expression & Math::Symbolic. 

# No need perl.
# For numbers all by their lonesome on a line.
awk 'BEGIN { sum = 0 } END { print sum } { sum += $1 }' in > out

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In reply to Re: Summing numbers in a file by parv
in thread Summing numbers in a file by pvfki

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