diff --git a/src/libcoreint/opcodes.c b/src/libcoreint/opcodes.c
index d682786e7..5961db133 100644
--- a/src/libcoreint/opcodes.c
+++ b/src/libcoreint/opcodes.c
@@ -204,7 +204,7 @@ opfunc_jmp (OPCODE opdata, struct __int_data *int_data)
  * See also: ECMA-262 v5, 11.13.1
  *
  * @return completion value
- *         Returned value must be freed with ecma_FreeCompletionValue
+ *         Returned value must be freed with ecma_free_completion_value
  */
 ecma_CompletionValue_t
 opfunc_assignment (OPCODE opdata, /**< operation data */
diff --git a/src/libecmaobjects/ecma-helpers-value.c b/src/libecmaobjects/ecma-helpers-value.c
index 98f0bae7c..455340df1 100644
--- a/src/libecmaobjects/ecma-helpers-value.c
+++ b/src/libecmaobjects/ecma-helpers-value.c
@@ -276,6 +276,18 @@ ecma_free_completion_value( ecma_CompletionValue_t completion_value) /**< comple
     }
 } /* ecma_free_completion_value */
 
+/**
+ * Check if the completion value is normal value.
+ *
+ * @return true - if the completion type is normal,
+ *         false - otherwise.
+ */
+bool
+ecma_is_completion_value_normal( ecma_CompletionValue_t value)
+{
+  return ( value.type == ECMA_COMPLETION_TYPE_NORMAL );
+} /* ecma_is_completion_value_normal */
+
 /**
  * Check if the completion value is specified normal simple value.
  *
diff --git a/src/libecmaobjects/ecma-helpers.h b/src/libecmaobjects/ecma-helpers.h
index 9561b478f..dbe890bd1 100644
--- a/src/libecmaobjects/ecma-helpers.h
+++ b/src/libecmaobjects/ecma-helpers.h
@@ -56,6 +56,7 @@ extern ecma_CompletionValue_t ecma_MakeCompletionValue( ecma_CompletionType_t ty
 extern ecma_CompletionValue_t ecma_MakeThrowValue( ecma_Object_t *exception_p);
 extern void ecma_free_completion_value( ecma_CompletionValue_t completion_value);
 
+extern bool ecma_is_completion_value_normal( ecma_CompletionValue_t value);
 extern bool ecma_is_completion_value_normal_simple_value( ecma_CompletionValue_t value, ecma_SimpleValue_t simple_value);
 extern bool ecma_IsCompletionValueNormalFalse( ecma_CompletionValue_t value);
 extern bool ecma_IsCompletionValueNormalTrue( ecma_CompletionValue_t value);
diff --git a/src/libecmaoperations/ecma-conversion.c b/src/libecmaoperations/ecma-conversion.c
index d9008b1f9..340904e31 100644
--- a/src/libecmaoperations/ecma-conversion.c
+++ b/src/libecmaoperations/ecma-conversion.c
@@ -35,7 +35,7 @@
  *          ECMA-262 v5, 9.10
  *
  * @return completion value
- *         Returned value must be free with ecma_FreeCompletionValue
+ *         Returned value must be freed with ecma_free_completion_value
  */
 ecma_CompletionValue_t
 ecma_op_check_object_coercible( ecma_Value_t value) /**< ecma-value */
@@ -87,10 +87,10 @@ ecma_op_check_object_coercible( ecma_Value_t value) /**< ecma-value */
  * ToPrimitive operation.
  *
  * See also:
- *          ECMA-262 v5, 9.10
+ *          ECMA-262 v5, 9.1
  *
  * @return completion value
- *         Returned value must be free with ecma_FreeCompletionValue
+ *         Returned value must be freed with ecma_free_completion_value
  */
 ecma_CompletionValue_t
 ecma_op_to_primitive( ecma_Value_t value) /**< ecma-value */
@@ -118,14 +118,58 @@ ecma_op_to_primitive( ecma_Value_t value) /**< ecma-value */
   JERRY_UNREACHABLE();
 } /* ecma_op_to_primitive */
 
+/**
+ * ToNumber operation.
+ *
+ * See also:
+ *          ECMA-262 v5, 9.3
+ *
+ * @return completion value
+ *         Returned value must be freed with ecma_free_completion_value
+ */
+ecma_CompletionValue_t
+ecma_op_to_number( ecma_Value_t value) /**< ecma-value */
+{
+  switch ( (ecma_Type_t)value.m_ValueType )
+  {
+    case ECMA_TYPE_NUMBER:
+      {
+        return ecma_MakeCompletionValue( ECMA_COMPLETION_TYPE_NORMAL,
+                                         ecma_CopyValue( value),
+                                         ECMA_TARGET_ID_RESERVED);
+      }
+    case ECMA_TYPE_SIMPLE:
+    case ECMA_TYPE_STRING:
+      {
+        JERRY_UNIMPLEMENTED();
+      }
+    case ECMA_TYPE_OBJECT:
+      {
+        ecma_CompletionValue_t completion_to_primitive = ecma_op_to_primitive( value);
+        JERRY_ASSERT( ecma_is_completion_value_normal( completion_to_primitive) );
+
+        ecma_CompletionValue_t completion_to_number = ecma_op_to_number( completion_to_primitive.value);
+        ecma_free_completion_value( completion_to_primitive);
+
+        return completion_to_number;
+      }
+    case ECMA_TYPE__COUNT:
+      {
+        JERRY_UNREACHABLE();
+      }
+  }
+
+  JERRY_UNREACHABLE();
+} /* ecma_op_to_number */
+
 /**
  * ToObject operation.
  *
  * See also:
- *          ECMA-262 v5, 9.10
+ *          ECMA-262 v5, 9.9
  *
  * @return completion value
- *         Returned value must be free with ecma_FreeCompletionValue
+ *         Returned value must be freed with ecma_free_completion_value
  */
 ecma_CompletionValue_t
 ecma_op_to_object( ecma_Value_t value) /**< ecma-value */
diff --git a/src/libecmaoperations/ecma-conversion.h b/src/libecmaoperations/ecma-conversion.h
index c52d101af..82980748b 100644
--- a/src/libecmaoperations/ecma-conversion.h
+++ b/src/libecmaoperations/ecma-conversion.h
@@ -28,6 +28,7 @@
 
 extern ecma_CompletionValue_t ecma_op_check_object_coercible( ecma_Value_t value);
 extern ecma_CompletionValue_t ecma_op_to_primitive( ecma_Value_t value);
+extern ecma_CompletionValue_t ecma_op_to_number( ecma_Value_t value);
 extern ecma_CompletionValue_t ecma_op_to_object( ecma_Value_t value);
 
 /**