diff --git a/README.md b/README.md
index 698e869..da26a41 100644
--- a/README.md
+++ b/README.md
@@ -3,5 +3,6 @@
 https://github.com/louisrubet/rpn/ inspired language in ruby
 
 # TODO-list
+  * generalize use of BigDecimal in :numeric's
   * pseudo filesystem: subdir for variables
   * UI toolkit (based on https://github.com/AndyObtiva/glimmer-dsl-libui ?)
diff --git a/spec/language_trig_spec.rb b/spec/language_trig_spec.rb
index 1065365..3893ce9 100644
--- a/spec/language_trig_spec.rb
+++ b/spec/language_trig_spec.rb
@@ -57,8 +57,9 @@ class TesttLanguageOperations < Test::Unit::TestCase
 
   def test_d→r
     lang = Rpl::Language.new
-    lang.run '30 d→r'
-    assert_equal [{ value: 0.5235987756, type: :numeric, base: 10 }],
+    lang.run '90 d→r'
+    assert_equal [{ value: BigDecimal( 1.57079632679489661923132169168272243847381663981000003, Rpl::Lang::Core.precision ),
+                    type: :numeric, base: 10 }],
                  lang.stack
   end