diff --git a/Number_types/include/CGAL/Sqrt_extension/Sqrt_extension_type.h b/Number_types/include/CGAL/Sqrt_extension/Sqrt_extension_type.h
index b7290aec11e..e49109e2421 100644
--- a/Number_types/include/CGAL/Sqrt_extension/Sqrt_extension_type.h
+++ b/Number_types/include/CGAL/Sqrt_extension/Sqrt_extension_type.h
@@ -195,9 +195,10 @@ public:
     > >::type* = 0  )
   {
     typename Fraction_traits<NT>::Compose compose_nt;
+    typename Fraction_traits<ROOT>::Compose compose_root;
     if ( a != 0 ) {
       a0_ = compose_nt(-b,2*a);
-      root_ = CGAL_NTS square(a0_) - ROOT(c,a);
+      root_ = CGAL_NTS square(a0_) - compose_root(c,a);
       if(CGAL_NTS is_zero(root_)) {
 	is_extended_ = false;
       } else {
diff --git a/Number_types/test/Number_types/root_of_2.cpp b/Number_types/test/Number_types/root_of_2.cpp
index 23ea3986d2a..0b221b7d5e2 100644
--- a/Number_types/test/Number_types/root_of_2.cpp
+++ b/Number_types/test/Number_types/root_of_2.cpp
@@ -127,8 +127,8 @@ CGAL::Sqrt_extension<double,double,Tag1,Tag2> create_root_helper(RT a, RT b,CGAL
 template < class T, class RT,class Tag1, class Tag2 >
 CGAL::Sqrt_extension<T,T,Tag1,Tag2> create_root_helper(RT a, RT b, CGAL::Sqrt_extension<T,T,Tag1,Tag2> *)
 {
-  T t(a,b);
-  return CGAL::Sqrt_extension<T,T,Tag1,Tag2>( t );
+  typename CGAL::Fraction_traits<T>::Compose comp;
+  return CGAL::Sqrt_extension<T,T,Tag1,Tag2>( comp(a, b) );
 }
 
 template < class Root, class RT >