class Float

def round(precision = nil)

x.round(2) # => 1.34
x.round(1) # => 1.3
x.round # => 1
x = 1.337

Rounds the float with the specified precision. 
def round(precision = nil)
  if precision
    magnitude = 10.0 ** precision
    (self * magnitude).round / magnitude
  else
    precisionless_round
  end
end