diff --git a/Exercises/4-methods.test b/Exercises/4-methods.test
index a408b22..78eb07d 100644
--- a/Exercises/4-methods.test
+++ b/Exercises/4-methods.test
@@ -10,11 +10,15 @@
         },
         m3(x, y, z) {
           return [x, y, z];
-        }
+        },
+        m4: function sum(x, y) {
+          return x + y;
+        },
       }, [
         ['m1', 1],
         ['m2', 2],
-        ['m3', 3]
+        ['m3', 3],
+        ['sum', 2],
       ]
     ],
   ]
diff --git a/Solutions/4-methods.js b/Solutions/4-methods.js
index 53ec1aa..46890b3 100644
--- a/Solutions/4-methods.js
+++ b/Solutions/4-methods.js
@@ -5,7 +5,7 @@ const methods = (iface) => {
   for (const name in iface) {
     const fn = iface[name];
     if (typeof fn === 'function') {
-      names.push([name, fn.length]);
+      names.push([fn.name, fn.length]);
     }
   }
   return names;