lib/luhn.rb in moeffju-luhn-0.1.2 vs lib/luhn.rb in moeffju-luhn-0.1.3

@@ -2,10 +2,10 @@
 
 class Numeric
   def luhn
     digits = self.to_s.chars.map(&:to_i)
     sum = digits.reverse.each_with_index.map{ |x, i| i.even? ? (x * 2).divmod(10).inject(:+) : x }.reverse.inject(:+)
-    (10 - sum % 10)
+    (10 - sum % 10) % 10
   end
 
   def luhn?
     self.div(10).luhn == (self % 10)
   end