--- a/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/runtime/JSType.java	Wed Jul 05 22:05:29 2017 +0200
+++ b/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/runtime/JSType.java	Tue Aug 16 15:04:51 2016 +0200
@@ -474,6 +474,8 @@
             return toPrimitive((ScriptObject)obj, hint);
         } else if (isPrimitive(obj)) {
             return obj;
+        } else if (hint == Number.class && obj instanceof Number) {
+            return ((Number) obj).doubleValue();
         } else if (obj instanceof JSObject) {
             return toPrimitive((JSObject)obj, hint);
         } else if (obj instanceof StaticClass) {