-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Pen, On Saturday 21 August 2010, Pen Ttt <myocean135 / yahoo.cn> wrote: > irb(main):012:0> format("%.2f",125%) 125% is, strictly spoken, not a number, but a number plus a unit. The unit is a character, not an integer, and this makes "125%" only valid as a string in Ruby. You've got to remove the "%" sign before you can treat "125" as a number. HTH. Eric -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (GNU/Linux) iEYEARECAAYFAkxvzWMACgkQhS0drJ3goJJmWwCaA1o2qvv0Tf1L4bsnAw7HJ95D xdUAoIbg/9wV+D1bdTBIUXsOL38dLqSy =SiNK -----END PGP SIGNATURE-----