Precentage proxy for Ruby's Numeric class

Just a little something i did, cause it usually takes me about 15 minutes to calculate a percentage conversion.
is anyone else checking/calculating dates in irb/console?
"Elad, in 2 weeks you have a dentist appointment!"
"mmm.... "


script/runner 'puts 2.weeks.from_now'


hehe,
but the method today's post is about, is the percent_from i did, so here it is.


class Numeric
def precent_from(num = 100)
self.to_f * (num.to_f / 100.0)
end
end


which comes out as:


>> 40.precent_from(1000)
=> 400.0
>> 6.precent_from(1000)
=> 60.0