diff --git a/src/Compiler/Checking/CheckExpressions.fs b/src/Compiler/Checking/CheckExpressions.fs
index 0e7fa94ba39..7bf3e5ee399 100644
--- a/src/Compiler/Checking/CheckExpressions.fs
+++ b/src/Compiler/Checking/CheckExpressions.fs
@@ -757,6 +757,7 @@ let rec TcSynRationalConst c =
   | SynRationalConst.Integer(value = i) -> intToRational i
   | SynRationalConst.Negate(rationalConst = c2) -> NegRational (TcSynRationalConst c2)
   | SynRationalConst.Rational(numerator = p; denominator = q) -> DivRational (intToRational p) (intToRational q)
+  | SynRationalConst.Paren(rationalConst = c) -> TcSynRationalConst c
 
 /// Typecheck constant terms in expressions and patterns
 let TcConst (cenv: cenv) (overallTy: TType) m env synConst =
diff --git a/src/Compiler/Service/ServiceInterfaceStubGenerator.fs b/src/Compiler/Service/ServiceInterfaceStubGenerator.fs
index 4f1c91ca373..cc56ba41494 100644
--- a/src/Compiler/Service/ServiceInterfaceStubGenerator.fs
+++ b/src/Compiler/Service/ServiceInterfaceStubGenerator.fs
@@ -106,8 +106,9 @@ type InterfaceData =
             let rec (|RationalConst|) =
                 function
                 | SynRationalConst.Integer (value = i) -> string i
-                | SynRationalConst.Rational (numerator = numerator; denominator = denominator) -> sprintf "(%i/%i)" numerator denominator
+                | SynRationalConst.Rational (numerator = numerator; denominator = denominator) -> sprintf "%i/%i" numerator denominator
                 | SynRationalConst.Negate (rationalConst = (RationalConst s)) -> sprintf "- %s" s
+                | SynRationalConst.Paren (rationalConst = (RationalConst s)) -> sprintf "(%s)" s
 
             let rec (|TypeIdent|_|) =
                 function
diff --git a/src/Compiler/SyntaxTree/SyntaxTree.fs b/src/Compiler/SyntaxTree/SyntaxTree.fs
index 0a82bb5dfbb..9ea664863dc 100644
--- a/src/Compiler/SyntaxTree/SyntaxTree.fs
+++ b/src/Compiler/SyntaxTree/SyntaxTree.fs
@@ -195,10 +195,12 @@ type SynRationalConst =
 
     | Integer of value: int32 * range: range
 
-    | Rational of numerator: int32 * numeratorRange: range * denominator: int32 * denominatorRange: range * range: range
+    | Rational of numerator: int32 * numeratorRange: range * divRange: range * denominator: int32 * denominatorRange: range * range: range
 
     | Negate of rationalConst: SynRationalConst * range: range
 
+    | Paren of rationalConst: SynRationalConst * range: range
+
 [<RequireQualifiedAccess>]
 type SynAccess =
     | Public of range: range
diff --git a/src/Compiler/SyntaxTree/SyntaxTree.fsi b/src/Compiler/SyntaxTree/SyntaxTree.fsi
index 1bb11f21d7c..0f1f6e858d6 100644
--- a/src/Compiler/SyntaxTree/SyntaxTree.fsi
+++ b/src/Compiler/SyntaxTree/SyntaxTree.fsi
@@ -216,10 +216,18 @@ type SynRationalConst =
 
     | Integer of value: int32 * range: range
 
-    | Rational of numerator: int32 * numeratorRange: range * denominator: int32 * denominatorRange: range * range: range
+    | Rational of
+        numerator: int32 *
+        numeratorRange: range *
+        divRange: range *
+        denominator: int32 *
+        denominatorRange: range *
+        range: range
 
     | Negate of rationalConst: SynRationalConst * range: range
 
+    | Paren of rationalConst: SynRationalConst * range: range
+
 /// Represents an accessibility modifier in F# syntax
 [<RequireQualifiedAccess>]
 type SynAccess =
diff --git a/src/Compiler/pars.fsy b/src/Compiler/pars.fsy
index 65fe63a6708..a6b398b3979 100644
--- a/src/Compiler/pars.fsy
+++ b/src/Compiler/pars.fsy
@@ -3314,13 +3314,13 @@ rationalConstant:
     { if $2 <> "/" then reportParseErrorAt (rhs parseState 2) (FSComp.SR.parsUnexpectedOperatorForUnitOfMeasure())
       if fst $3 = 0 then reportParseErrorAt (rhs parseState 3) (FSComp.SR.parsIllegalDenominatorForMeasureExponent())
       if (snd $1) || (snd $3) then errorR(Error(FSComp.SR.lexOutsideThirtyTwoBitSigned(), lhs parseState))
-      SynRationalConst.Rational(fst $1, rhs parseState 1, fst $3, rhs parseState 3, lhs parseState) }
+      SynRationalConst.Rational(fst $1, rhs parseState 1, rhs parseState 2, fst $3, rhs parseState 3, lhs parseState) }
 
   | MINUS INT32 INFIX_STAR_DIV_MOD_OP INT32
     { if $3 <> "/" then reportParseErrorAt (rhs parseState 3) (FSComp.SR.parsUnexpectedOperatorForUnitOfMeasure())
       if fst $4 = 0 then reportParseErrorAt (rhs parseState 4) (FSComp.SR.parsIllegalDenominatorForMeasureExponent())
       if (snd $2) || (snd $4) then errorR(Error(FSComp.SR.lexOutsideThirtyTwoBitSigned(), lhs parseState))
-      SynRationalConst.Negate(SynRationalConst.Rational(fst $2, rhs parseState 2, fst $4, rhs parseState 4, lhs parseState), lhs parseState) }
+      SynRationalConst.Negate(SynRationalConst.Rational(fst $2, rhs parseState 2, rhs parseState 3, fst $4, rhs parseState 4, lhs parseState), lhs parseState) }
 
   | INT32
     { if snd $1 then errorR(Error(FSComp.SR.lexOutsideThirtyTwoBitSigned(), lhs parseState))
@@ -3335,7 +3335,7 @@ atomicUnsignedRationalConstant:
             SynRationalConst.Integer(fst $1, lhs parseState) }
 
   | LPAREN rationalConstant rparen
-    { $2 }
+    { SynRationalConst.Paren($2, rhs2 parseState 1 3) }
 
 atomicRationalConstant:
   | atomicUnsignedRationalConstant { $1 }
diff --git a/tests/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.SurfaceArea.netstandard20.debug.bsl b/tests/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.SurfaceArea.netstandard20.debug.bsl
index ae6c5c79079..92ea2574c7a 100644
--- a/tests/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.SurfaceArea.netstandard20.debug.bsl
+++ b/tests/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.SurfaceArea.netstandard20.debug.bsl
@@ -8238,8 +8238,14 @@ FSharp.Compiler.Syntax.SynRationalConst+Negate: FSharp.Compiler.Syntax.SynRation
 FSharp.Compiler.Syntax.SynRationalConst+Negate: FSharp.Compiler.Syntax.SynRationalConst rationalConst
 FSharp.Compiler.Syntax.SynRationalConst+Negate: FSharp.Compiler.Text.Range get_range()
 FSharp.Compiler.Syntax.SynRationalConst+Negate: FSharp.Compiler.Text.Range range
+FSharp.Compiler.Syntax.SynRationalConst+Paren: FSharp.Compiler.Syntax.SynRationalConst get_rationalConst()
+FSharp.Compiler.Syntax.SynRationalConst+Paren: FSharp.Compiler.Syntax.SynRationalConst rationalConst
+FSharp.Compiler.Syntax.SynRationalConst+Paren: FSharp.Compiler.Text.Range get_range()
+FSharp.Compiler.Syntax.SynRationalConst+Paren: FSharp.Compiler.Text.Range range
 FSharp.Compiler.Syntax.SynRationalConst+Rational: FSharp.Compiler.Text.Range denominatorRange
+FSharp.Compiler.Syntax.SynRationalConst+Rational: FSharp.Compiler.Text.Range divRange
 FSharp.Compiler.Syntax.SynRationalConst+Rational: FSharp.Compiler.Text.Range get_denominatorRange()
+FSharp.Compiler.Syntax.SynRationalConst+Rational: FSharp.Compiler.Text.Range get_divRange()
 FSharp.Compiler.Syntax.SynRationalConst+Rational: FSharp.Compiler.Text.Range get_numeratorRange()
 FSharp.Compiler.Syntax.SynRationalConst+Rational: FSharp.Compiler.Text.Range get_range()
 FSharp.Compiler.Syntax.SynRationalConst+Rational: FSharp.Compiler.Text.Range numeratorRange
@@ -8250,18 +8256,23 @@ FSharp.Compiler.Syntax.SynRationalConst+Rational: Int32 get_numerator()
 FSharp.Compiler.Syntax.SynRationalConst+Rational: Int32 numerator
 FSharp.Compiler.Syntax.SynRationalConst+Tags: Int32 Integer
 FSharp.Compiler.Syntax.SynRationalConst+Tags: Int32 Negate
+FSharp.Compiler.Syntax.SynRationalConst+Tags: Int32 Paren
 FSharp.Compiler.Syntax.SynRationalConst+Tags: Int32 Rational
 FSharp.Compiler.Syntax.SynRationalConst: Boolean IsInteger
 FSharp.Compiler.Syntax.SynRationalConst: Boolean IsNegate
+FSharp.Compiler.Syntax.SynRationalConst: Boolean IsParen
 FSharp.Compiler.Syntax.SynRationalConst: Boolean IsRational
 FSharp.Compiler.Syntax.SynRationalConst: Boolean get_IsInteger()
 FSharp.Compiler.Syntax.SynRationalConst: Boolean get_IsNegate()
+FSharp.Compiler.Syntax.SynRationalConst: Boolean get_IsParen()
 FSharp.Compiler.Syntax.SynRationalConst: Boolean get_IsRational()
 FSharp.Compiler.Syntax.SynRationalConst: FSharp.Compiler.Syntax.SynRationalConst NewInteger(Int32, FSharp.Compiler.Text.Range)
 FSharp.Compiler.Syntax.SynRationalConst: FSharp.Compiler.Syntax.SynRationalConst NewNegate(FSharp.Compiler.Syntax.SynRationalConst, FSharp.Compiler.Text.Range)
-FSharp.Compiler.Syntax.SynRationalConst: FSharp.Compiler.Syntax.SynRationalConst NewRational(Int32, FSharp.Compiler.Text.Range, Int32, FSharp.Compiler.Text.Range, FSharp.Compiler.Text.Range)
+FSharp.Compiler.Syntax.SynRationalConst: FSharp.Compiler.Syntax.SynRationalConst NewParen(FSharp.Compiler.Syntax.SynRationalConst, FSharp.Compiler.Text.Range)
+FSharp.Compiler.Syntax.SynRationalConst: FSharp.Compiler.Syntax.SynRationalConst NewRational(Int32, FSharp.Compiler.Text.Range, FSharp.Compiler.Text.Range, Int32, FSharp.Compiler.Text.Range, FSharp.Compiler.Text.Range)
 FSharp.Compiler.Syntax.SynRationalConst: FSharp.Compiler.Syntax.SynRationalConst+Integer
 FSharp.Compiler.Syntax.SynRationalConst: FSharp.Compiler.Syntax.SynRationalConst+Negate
+FSharp.Compiler.Syntax.SynRationalConst: FSharp.Compiler.Syntax.SynRationalConst+Paren
 FSharp.Compiler.Syntax.SynRationalConst: FSharp.Compiler.Syntax.SynRationalConst+Rational
 FSharp.Compiler.Syntax.SynRationalConst: FSharp.Compiler.Syntax.SynRationalConst+Tags
 FSharp.Compiler.Syntax.SynRationalConst: Int32 Tag
diff --git a/tests/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.SurfaceArea.netstandard20.release.bsl b/tests/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.SurfaceArea.netstandard20.release.bsl
index ae6c5c79079..92ea2574c7a 100644
--- a/tests/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.SurfaceArea.netstandard20.release.bsl
+++ b/tests/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.SurfaceArea.netstandard20.release.bsl
@@ -8238,8 +8238,14 @@ FSharp.Compiler.Syntax.SynRationalConst+Negate: FSharp.Compiler.Syntax.SynRation
 FSharp.Compiler.Syntax.SynRationalConst+Negate: FSharp.Compiler.Syntax.SynRationalConst rationalConst
 FSharp.Compiler.Syntax.SynRationalConst+Negate: FSharp.Compiler.Text.Range get_range()
 FSharp.Compiler.Syntax.SynRationalConst+Negate: FSharp.Compiler.Text.Range range
+FSharp.Compiler.Syntax.SynRationalConst+Paren: FSharp.Compiler.Syntax.SynRationalConst get_rationalConst()
+FSharp.Compiler.Syntax.SynRationalConst+Paren: FSharp.Compiler.Syntax.SynRationalConst rationalConst
+FSharp.Compiler.Syntax.SynRationalConst+Paren: FSharp.Compiler.Text.Range get_range()
+FSharp.Compiler.Syntax.SynRationalConst+Paren: FSharp.Compiler.Text.Range range
 FSharp.Compiler.Syntax.SynRationalConst+Rational: FSharp.Compiler.Text.Range denominatorRange
+FSharp.Compiler.Syntax.SynRationalConst+Rational: FSharp.Compiler.Text.Range divRange
 FSharp.Compiler.Syntax.SynRationalConst+Rational: FSharp.Compiler.Text.Range get_denominatorRange()
+FSharp.Compiler.Syntax.SynRationalConst+Rational: FSharp.Compiler.Text.Range get_divRange()
 FSharp.Compiler.Syntax.SynRationalConst+Rational: FSharp.Compiler.Text.Range get_numeratorRange()
 FSharp.Compiler.Syntax.SynRationalConst+Rational: FSharp.Compiler.Text.Range get_range()
 FSharp.Compiler.Syntax.SynRationalConst+Rational: FSharp.Compiler.Text.Range numeratorRange
@@ -8250,18 +8256,23 @@ FSharp.Compiler.Syntax.SynRationalConst+Rational: Int32 get_numerator()
 FSharp.Compiler.Syntax.SynRationalConst+Rational: Int32 numerator
 FSharp.Compiler.Syntax.SynRationalConst+Tags: Int32 Integer
 FSharp.Compiler.Syntax.SynRationalConst+Tags: Int32 Negate
+FSharp.Compiler.Syntax.SynRationalConst+Tags: Int32 Paren
 FSharp.Compiler.Syntax.SynRationalConst+Tags: Int32 Rational
 FSharp.Compiler.Syntax.SynRationalConst: Boolean IsInteger
 FSharp.Compiler.Syntax.SynRationalConst: Boolean IsNegate
+FSharp.Compiler.Syntax.SynRationalConst: Boolean IsParen
 FSharp.Compiler.Syntax.SynRationalConst: Boolean IsRational
 FSharp.Compiler.Syntax.SynRationalConst: Boolean get_IsInteger()
 FSharp.Compiler.Syntax.SynRationalConst: Boolean get_IsNegate()
+FSharp.Compiler.Syntax.SynRationalConst: Boolean get_IsParen()
 FSharp.Compiler.Syntax.SynRationalConst: Boolean get_IsRational()
 FSharp.Compiler.Syntax.SynRationalConst: FSharp.Compiler.Syntax.SynRationalConst NewInteger(Int32, FSharp.Compiler.Text.Range)
 FSharp.Compiler.Syntax.SynRationalConst: FSharp.Compiler.Syntax.SynRationalConst NewNegate(FSharp.Compiler.Syntax.SynRationalConst, FSharp.Compiler.Text.Range)
-FSharp.Compiler.Syntax.SynRationalConst: FSharp.Compiler.Syntax.SynRationalConst NewRational(Int32, FSharp.Compiler.Text.Range, Int32, FSharp.Compiler.Text.Range, FSharp.Compiler.Text.Range)
+FSharp.Compiler.Syntax.SynRationalConst: FSharp.Compiler.Syntax.SynRationalConst NewParen(FSharp.Compiler.Syntax.SynRationalConst, FSharp.Compiler.Text.Range)
+FSharp.Compiler.Syntax.SynRationalConst: FSharp.Compiler.Syntax.SynRationalConst NewRational(Int32, FSharp.Compiler.Text.Range, FSharp.Compiler.Text.Range, Int32, FSharp.Compiler.Text.Range, FSharp.Compiler.Text.Range)
 FSharp.Compiler.Syntax.SynRationalConst: FSharp.Compiler.Syntax.SynRationalConst+Integer
 FSharp.Compiler.Syntax.SynRationalConst: FSharp.Compiler.Syntax.SynRationalConst+Negate
+FSharp.Compiler.Syntax.SynRationalConst: FSharp.Compiler.Syntax.SynRationalConst+Paren
 FSharp.Compiler.Syntax.SynRationalConst: FSharp.Compiler.Syntax.SynRationalConst+Rational
 FSharp.Compiler.Syntax.SynRationalConst: FSharp.Compiler.Syntax.SynRationalConst+Tags
 FSharp.Compiler.Syntax.SynRationalConst: Int32 Tag
diff --git a/tests/service/data/SyntaxTree/Measure/Constant - 07.fs.bsl b/tests/service/data/SyntaxTree/Measure/Constant - 07.fs.bsl
index 1485e64fd8c..db9e83c0fb8 100644
--- a/tests/service/data/SyntaxTree/Measure/Constant - 07.fs.bsl	
+++ b/tests/service/data/SyntaxTree/Measure/Constant - 07.fs.bsl	
@@ -10,9 +10,11 @@ ImplFile
                     Seq
                       ([Power
                           (Named ([kg], (3,3--3,5)), (3,8--3,9),
-                           Rational
-                             (-12345, (3,21--3,27), 123, (3,28--3,31),
-                              (3,21--3,31)), (3,3--3,32))], (3,3--3,32)),
+                           Paren
+                             (Rational
+                                (-12345, (3,21--3,27), (3,27--3,28), 123,
+                                 (3,28--3,31), (3,21--3,31)), (3,20--3,32)),
+                           (3,3--3,32))], (3,3--3,32)),
                     { LessRange = (3,2--3,3)
                       GreaterRange = (3,32--3,33) }), (3,0--3,33)), (3,0--3,33))],
           PreXmlDoc ((1,0), FSharp.Compiler.Xml.XmlDocCollector), [], None,
diff --git a/tests/service/data/SyntaxTree/Measure/Constant - 08.fs.bsl b/tests/service/data/SyntaxTree/Measure/Constant - 08.fs.bsl
index cdc20a7bbe4..b4a8f0b48c2 100644
--- a/tests/service/data/SyntaxTree/Measure/Constant - 08.fs.bsl	
+++ b/tests/service/data/SyntaxTree/Measure/Constant - 08.fs.bsl	
@@ -11,12 +11,13 @@ ImplFile
                       ([Power
                           (Named ([kg], (3,3--3,5)), (3,5--3,6),
                            Negate
-                             (Rational
-                                (12345, (3,13--3,18), 123, (3,19--3,22),
-                                 (3,13--3,22)), (3,6--3,23)), (3,3--3,23))],
-                       (3,3--3,23)), { LessRange = (3,2--3,3)
-                                       GreaterRange = (3,23--3,24) }),
-                 (3,0--3,24)), (3,0--3,24))],
+                             (Paren
+                                (Rational
+                                   (12345, (3,13--3,18), (3,18--3,19), 123,
+                                    (3,19--3,22), (3,13--3,22)), (3,12--3,23)),
+                              (3,6--3,23)), (3,3--3,23))], (3,3--3,23)),
+                    { LessRange = (3,2--3,3)
+                      GreaterRange = (3,23--3,24) }), (3,0--3,24)), (3,0--3,24))],
           PreXmlDoc ((1,0), FSharp.Compiler.Xml.XmlDocCollector), [], None,
           (1,0--3,24), { LeadingKeyword = Module (1,0--1,6) })], (true, true),
       { ConditionalDirectives = []
diff --git a/tests/service/data/SyntaxTree/Measure/Constant - 09.fs.bsl b/tests/service/data/SyntaxTree/Measure/Constant - 09.fs.bsl
index 83f101df01a..2eeee44a379 100644
--- a/tests/service/data/SyntaxTree/Measure/Constant - 09.fs.bsl	
+++ b/tests/service/data/SyntaxTree/Measure/Constant - 09.fs.bsl	
@@ -11,12 +11,13 @@ ImplFile
                       ([Power
                           (Named ([kg], (3,3--3,5)), (3,5--3,6),
                            Negate
-                             (Rational
-                                (12345, (3,10--3,15), 123, (3,16--3,19),
-                                 (3,10--3,19)), (3,7--3,20)), (3,3--3,20))],
-                       (3,3--3,20)), { LessRange = (3,2--3,3)
-                                       GreaterRange = (3,20--3,21) }),
-                 (3,0--3,21)), (3,0--3,21))],
+                             (Paren
+                                (Rational
+                                   (12345, (3,10--3,15), (3,15--3,16), 123,
+                                    (3,16--3,19), (3,10--3,19)), (3,9--3,20)),
+                              (3,7--3,20)), (3,3--3,20))], (3,3--3,20)),
+                    { LessRange = (3,2--3,3)
+                      GreaterRange = (3,20--3,21) }), (3,0--3,21)), (3,0--3,21))],
           PreXmlDoc ((1,0), FSharp.Compiler.Xml.XmlDocCollector), [], None,
           (1,0--3,21), { LeadingKeyword = Module (1,0--1,6) })], (true, true),
       { ConditionalDirectives = []