$ perl -le 'print "Wrong " if 19.08 + 2.01 != 21.09;'
Wrong

##</code><code>##

$ perl -le 'print 21.09 - (19.08 + 2.01), "\n";'
3.5527136788005e-15

##</code><code>##

$ perl -le '$epsilon = 1e-14; print "Wrong " if abs (19.08 + 2.01 - 21.09) > $epsilon;'

$ perl -le '$epsilon = 1e-14; print "Wrong " if abs (19.08 + 2.02 - 21.09) > $epsilon;'
Wrong

##</code><code>##

$ perl -le 'use bigint; print "Wrong " if 19.08 + 2.01 != 21.09;'

$ perl -le 'use bigint; print 21.09 - (19.08 + 2.01), "\n";'
0