diff --git a/src/TensorFlowNET.Core/APIs/tf.math.cs b/src/TensorFlowNET.Core/APIs/tf.math.cs
index dc70344a..5d74a4df 100644
--- a/src/TensorFlowNET.Core/APIs/tf.math.cs
+++ b/src/TensorFlowNET.Core/APIs/tf.math.cs
@@ -26,9 +26,22 @@ namespace Tensorflow
             return gen_math_ops.pow(x, y);
         }
 
+        /// <summary>
+        /// Computes the sum of elements across dimensions of a tensor.
+        /// </summary>
+        /// <param name="input"></param>
+        /// <param name="axis"></param>
+        /// <returns></returns>
         public static Tensor reduce_sum(Tensor input, int[] axis = null)
         {
-            return gen_math_ops.sum(input, axis);
+            Tensor rank;
+            using (var namescop = new ops.name_scope<Tensor>("", "Rank", new List<Tensor> { input }))
+            {
+                string name = namescop;
+                rank = gen_array_ops.rank(input, name);
+            }
+            var s = gen_math_ops.sum(input, rank);
+            return gen_math_ops.range(0, s);
         }
     }
 }
diff --git a/src/TensorFlowNET.Core/Operations/gen_array_ops.cs b/src/TensorFlowNET.Core/Operations/gen_array_ops.cs
index b08d5e1f..560f6173 100644
--- a/src/TensorFlowNET.Core/Operations/gen_array_ops.cs
+++ b/src/TensorFlowNET.Core/Operations/gen_array_ops.cs
@@ -41,5 +41,15 @@ namespace Tensorflow
 
             return _op.outputs[0];
         }
+
+        public static Tensor rank(Tensor input, string name = "")
+        {
+            var keywords = new Dictionary<string, object>();
+            keywords.Add("input", input);
+
+            var _op = _op_def_lib._apply_op_helper("Rank", name: name, keywords: keywords);
+
+            return _op.outputs[0];
+        }
     }
 }
diff --git a/src/TensorFlowNET.Core/Operations/gen_math_ops.cs b/src/TensorFlowNET.Core/Operations/gen_math_ops.cs
index a7cfce43..91e7e629 100644
--- a/src/TensorFlowNET.Core/Operations/gen_math_ops.cs
+++ b/src/TensorFlowNET.Core/Operations/gen_math_ops.cs
@@ -78,17 +78,43 @@ namespace Tensorflow
             return new Tensor(_op, 0, _op.OutputType(0));
         }
 
-        public static Tensor sum(Tensor input, int[] axis = null)
+        public static Tensor sum(Tensor input, Tensor axis = null)
         {
-            if(axis == null) axis = new int[0];
             var keywords = new Dictionary<string, object>();
             keywords.Add("input", input);
-            keywords.Add("reduction_indices", constant_op.Constant(axis));
+            keywords.Add("reduction_indices", axis);
             keywords.Add("keep_dims", false);
 
             var _op = _op_def_lib._apply_op_helper("Sum", keywords: keywords);
 
             return new Tensor(_op, 0, _op.OutputType(0));
         }
+
+        /// <summary>
+        /// Creates a sequence of numbers.
+        /// </summary>
+        /// <param name="start"></param>
+        /// <param name="limit"></param>
+        /// <param name="delta"></param>
+        /// <param name="name"></param>
+        /// <returns></returns>
+        public static Tensor range(int start, Tensor limit, int delta = 1)
+        {
+            using (var namescope = new ops.name_scope<Tensor>("", "Range", new List<Tensor> { start, limit, delta }))
+            {
+                var start1 = ops.convert_to_tensor(start, "start");
+                var limit1 = ops.convert_to_tensor(limit, "limit");
+                var delta1 = ops.convert_to_tensor(delta, "delta");
+
+                var keywords = new Dictionary<string, object>();
+                keywords.Add("start", start1);
+                keywords.Add("limit", limit1);
+                keywords.Add("delta", delta1);
+
+                var _op = _op_def_lib._apply_op_helper("Range", namescope, keywords);
+
+                return _op.outputs[0];
+            }
+        }
     }
 }