diff --git a/CGAL_Core/include/CGAL/CORE/Expr.h b/CGAL_Core/include/CGAL/CORE/Expr.h
index 0c910979286..c10fb5fc560 100644
--- a/CGAL_Core/include/CGAL/CORE/Expr.h
+++ b/CGAL_Core/include/CGAL/CORE/Expr.h
@@ -93,7 +93,7 @@ public:
   Expr(const BigRat& R) : RCExpr(new ConstRealRep(Real(R))) {}
   /// constructor for <tt>BigRat expression</tt>
   template <class BigRatExpr, class = std::enable_if_t< boost::multiprecision::is_number_expression<BigRatExpr>::value> >
-  explicit Expr(const BigRatExpr& R) : RCExpr(new ConstRealRep(Real(BigRat(R)))) {}
+  Expr(const BigRatExpr& R) : RCExpr(new ConstRealRep(Real(BigRat(R)))) {}
 
   /// constructor for <tt>BigFloat</tt>
   Expr(const BigFloat& F) : RCExpr(new ConstRealRep(Real(F))) {}
diff --git a/Number_types/include/CGAL/CORE_BigFloat.h b/Number_types/include/CGAL/CORE_BigFloat.h
index 11934a244b9..81e9fcbaca6 100644
--- a/Number_types/include/CGAL/CORE_BigFloat.h
+++ b/Number_types/include/CGAL/CORE_BigFloat.h
@@ -326,7 +326,7 @@ public:
           NT w = Width()(x);
           w /= ::CORE::BigFloat(x.m()-x.err(),0,x.exp());
           w = w.abs();
-          return -(CORE::ceilLg(w.m()+w.err())+w.exp()*CORE::CHUNK_BIT);
+          return -(CORE::ceilLg(CORE::BigInt(w.m()+w.err()))+w.exp()*CORE::CHUNK_BIT);
         }
     };