Rubby numeric handling

gistfile1.txt

> require 'bigdecimal'
=> true
> Float('foo')
ArgumentError: invalid value for Float(): "foo"
	from (irb):2:in `Float'
	from (irb):2
	from /Users/mikep/.rubies/ruby-2.0.0-p353/bin/irb:12:in `<main>'
> Integer('foo')
ArgumentError: invalid value for Integer(): "foo"
	from (irb):3:in `Integer'
	from (irb):3
	from /Users/mikep/.rubies/ruby-2.0.0-p353/bin/irb:12:in `<main>'
> BigDecimal('foo')
=> #<BigDecimal:7fccf7178fb0,'0.0',9(9)>