diff --git a/activesupport/lib/active_support/number_helper/number_to_currency_converter.rb b/activesupport/lib/active_support/number_helper/number_to_currency_converter.rb
index 91e324a478..4b8d267b4e 100644
--- a/activesupport/lib/active_support/number_helper/number_to_currency_converter.rb
+++ b/activesupport/lib/active_support/number_helper/number_to_currency_converter.rb
@@ -9,12 +9,13 @@ module ActiveSupport
 
       def convert
         number = self.number.to_s.strip
+        number_f = number.to_f
         format = options[:format]
 
-        if number.to_f.negative?
-          number = absolute_value(number)
+        if number_f.negative?
+          number = number_f.abs
 
-          unless options[:precision] == 0 && number.to_f < 0.5
+          unless options[:precision] == 0 && number < 0.5
             format = options[:negative_format]
           end
         end
@@ -24,10 +25,6 @@ module ActiveSupport
       end
 
       private
-        def absolute_value(number)
-          number.respond_to?(:abs) ? number.abs : number.sub(/\A-/, "")
-        end
-
         def options
           @options ||= begin
             defaults = default_format_options.merge(i18n_opts)