Try the following:
echo 1.8e-308 | gawk '($1+0)<0.05'
produces:
1.8e-308
Some other interesting observations:
echo "True" | gawk '1.8e-308<0.05'
gives
True
and
echo "True" | gawk '1.8e-322<1.9e-322'
gives
True
whereas
echo "True" | gawk '1.8e-323<1.9e-323'
gives nothing..