--- a/Fraction.st	Wed Nov 20 16:32:58 2019 +0100
+++ b/Fraction.st	Wed Nov 20 16:33:31 2019 +0100
@@ -17,7 +17,7 @@
 
 Number subclass:#Fraction
 	instanceVariableNames:'numerator denominator'
-	classVariableNames:'FractionOne FractionZero PrintWholeNumbers Pi Pi_1000 E'
+	classVariableNames:'FractionOne FractionZero PrintWholeNumbers Pi Pi_1000 E Phi'
 	poolDictionaries:''
 	category:'Magnitude-Numbers'
 !
@@ -324,6 +324,28 @@
     "Created: / 03-07-2017 / 17:21:38 / cg"
 !
 
+phi
+    "return an approximation of the constant phi as Fraction.
+     The approx. returned here has an error smaller than representable by float instances
+     (roughly 26 valid digits)"
+
+    Phi isNil ifTrue:[
+        Phi := self
+            numerator:  161803398874989484820458683
+            denominator:100000000000000000000000000
+    ].
+    ^ Phi
+    
+    "
+     Fraction phi
+     Fraction phi asFloat - Float phi
+     Fraction phi asLongFloat - LongFloat phi
+     Float phi
+    "
+
+    "Modified (comment): / 03-07-2017 / 13:21:03 / cg"
+!
+
 pi
     "return an approximation of the constant pi as Fraction.
      The approx. returned here has an error smaller than representable by float instances