$ perl -le 'print abs(5056.45 + 10112.92 - 15169.37) < 0.0001 ? "as expected" : "perl math sucks!"'
as expected

$ perl -le 'print sprintf("%.4f", 5056.45 + 10112.92) eq sprintf("%.4f", 15169.37) ? "as expected" : "perl math sucks!"'
as expected