diff --git a/src/TensorFlowNET.Core/APIs/tf.math.cs b/src/TensorFlowNET.Core/APIs/tf.math.cs
index 741b4ccb..48672e32 100644
--- a/src/TensorFlowNET.Core/APIs/tf.math.cs
+++ b/src/TensorFlowNET.Core/APIs/tf.math.cs
@@ -6,29 +6,29 @@ namespace Tensorflow
 {
     public static partial class tf
     {
-        public static unsafe Tensor add(Tensor a, Tensor b)
+        public static Tensor add(Tensor a, Tensor b)
         {
             return gen_math_ops.add(a, b);
         }
 
-        public static unsafe Tensor sub(Tensor a, Tensor b)
+        public static Tensor sub(Tensor a, Tensor b)
         {
             return gen_math_ops.sub(a, b);
         }
 
-        public static unsafe Tensor add(Tensor a, RefVariable b)
+        public static Tensor multiply(Tensor x, Tensor y)
         {
-            return gen_math_ops.add(a, b);
+            return gen_math_ops.mul(x, y);
         }
 
-        public static unsafe Tensor multiply(Tensor x, Tensor y)
+        public static Tensor pow(Tensor x, Tensor y)
         {
-            return gen_math_ops.mul(x, y);
+            return gen_math_ops.pow(x, y);
         }
 
-        public static unsafe Tensor multiply(Tensor x, RefVariable y)
+        public static Tensor reduce_sum(Tensor input, int? axis = null)
         {
-            return gen_math_ops.mul(x, y);
+            return gen_math_ops.sum(input, input);
         }
     }
 }
diff --git a/src/TensorFlowNET.Core/Operations/OpDefLibrary.cs b/src/TensorFlowNET.Core/Operations/OpDefLibrary.cs
index 8e19be1c..9b9076c8 100644
--- a/src/TensorFlowNET.Core/Operations/OpDefLibrary.cs
+++ b/src/TensorFlowNET.Core/Operations/OpDefLibrary.cs
@@ -36,50 +36,27 @@ namespace Tensorflow
             foreach (var input_arg in op_def.InputArg)
             {
                 var input_name = input_arg.Name;
-                switch (keywords[input_name])
+                if (keywords[input_name] is Tensor value)
                 {
-                    case Tensor value:
-                        if (keywords.ContainsKey(input_name))
-                        {
-                            inputs.Add(value);
-                        }
-
-                        if (!String.IsNullOrEmpty(input_arg.TypeAttr))
-                        {
-                            attrs[input_arg.TypeAttr] = value.dtype;
-                        }
-
-                        if (input_arg.IsRef)
-                        {
-
-                        }
-                        else
-                        {
-                            input_types.Add(value.dtype);
-                        }
-                        break;
-                    case RefVariable value:
-                        if (keywords.ContainsKey(input_name))
-                        {
-                            inputs.Add(value._initial_value);
-                        }
-
-                        if (!String.IsNullOrEmpty(input_arg.TypeAttr))
-                        {
-                            attrs[input_arg.TypeAttr] = value._initial_value.dtype;
-                        }
-
-                        if (input_arg.IsRef)
-                        {
-
-                        }
-                        else
-                        {
-                            input_types.Add(value._initial_value.dtype);
-                        }
-                        break;
+                    if (keywords.ContainsKey(input_name))
+                    {
+                        inputs.Add(value);
+                    }
+
+                    if (!String.IsNullOrEmpty(input_arg.TypeAttr))
+                    {
+                        attrs[input_arg.TypeAttr] = value.dtype;
+                    }
+
+                    if (input_arg.IsRef)
+                    {
+
+                    }
+                    else
+                    {
+                        input_types.Add(value.dtype);
+                    }
                 }
-
             }
 
             // Process remaining attrs
diff --git a/src/TensorFlowNET.Core/Operations/gen_math_ops.cs b/src/TensorFlowNET.Core/Operations/gen_math_ops.cs
index 938c954e..66e2811c 100644
--- a/src/TensorFlowNET.Core/Operations/gen_math_ops.cs
+++ b/src/TensorFlowNET.Core/Operations/gen_math_ops.cs
@@ -20,59 +20,59 @@ namespace Tensorflow
             return new Tensor(_op, 0, _op.OutputType(0));
         }
 
-        public static Tensor add(Tensor a, RefVariable b)
+        public static Tensor sub(Tensor x, Tensor y)
         {
             var keywords = new Dictionary<string, object>();
-            keywords.Add("x", a);
-            keywords.Add("y", b);
+            keywords.Add("x", x);
+            keywords.Add("y", y);
 
-            var _op = _op_def_lib._apply_op_helper("Add", name: "add", keywords: keywords);
+            var _op = _op_def_lib._apply_op_helper("Sub", name: "sub", keywords: keywords);
 
             return new Tensor(_op, 0, _op.OutputType(0));
         }
 
-        public static Tensor sub(Tensor x, Tensor y)
+        public static Tensor mul(Tensor x, Tensor y)
         {
             var keywords = new Dictionary<string, object>();
             keywords.Add("x", x);
             keywords.Add("y", y);
 
-            var _op = _op_def_lib._apply_op_helper("Sub", name: "sub", keywords: keywords);
+            var _op = _op_def_lib._apply_op_helper("Mul", name: "mul", keywords: keywords);
 
             return new Tensor(_op, 0, _op.OutputType(0));
         }
 
-        public static Tensor mul(Tensor x, Tensor y)
+        public static Tensor mat_mul(Tensor a, Tensor b, bool transpose_a = false, bool transpose_b = false)
         {
             var keywords = new Dictionary<string, object>();
-            keywords.Add("x", x);
-            keywords.Add("y", y);
+            keywords.Add("a", a);
+            keywords.Add("b", b);
+            keywords.Add("transpose_a", transpose_a);
+            keywords.Add("transpose_b", transpose_b);
 
-            var _op = _op_def_lib._apply_op_helper("Mul", name: "mul", keywords: keywords);
+            var _op = _op_def_lib._apply_op_helper("MatMul", name: "MatMul", keywords: keywords);
 
             return new Tensor(_op, 0, _op.OutputType(0));
         }
 
-        public static Tensor mul(Tensor x, RefVariable y)
+        public static Tensor pow(Tensor x, Tensor y)
         {
             var keywords = new Dictionary<string, object>();
             keywords.Add("x", x);
             keywords.Add("y", y);
 
-            var _op = _op_def_lib._apply_op_helper("Mul", name: "mul", keywords: keywords);
+            var _op = _op_def_lib._apply_op_helper("Pow", name: "Pow", keywords: keywords);
 
             return new Tensor(_op, 0, _op.OutputType(0));
         }
 
-        public static Tensor mat_mul(Tensor a, Tensor b, bool transpose_a = false, bool transpose_b = false)
+        public static Tensor sum(Tensor x, Tensor y)
         {
             var keywords = new Dictionary<string, object>();
-            keywords.Add("a", a);
-            keywords.Add("b", b);
-            keywords.Add("transpose_a", transpose_a);
-            keywords.Add("transpose_b", transpose_b);
+            keywords.Add("x", x);
+            keywords.Add("y", y);
 
-            var _op = _op_def_lib._apply_op_helper("MatMul", name: "MatMul", keywords: keywords);
+            var _op = _op_def_lib._apply_op_helper("Pow", name: "Pow", keywords: keywords);
 
             return new Tensor(_op, 0, _op.OutputType(0));
         }
diff --git a/src/TensorFlowNET.Core/Sessions/BaseSession.cs b/src/TensorFlowNET.Core/Sessions/BaseSession.cs
index f74e3498..66138150 100644
--- a/src/TensorFlowNET.Core/Sessions/BaseSession.cs
+++ b/src/TensorFlowNET.Core/Sessions/BaseSession.cs
@@ -47,7 +47,7 @@ namespace Tensorflow
             return result;
         }
 
-        private unsafe object _run(Tensor fetches, Dictionary<Tensor, NDArray> feed_dict = null)
+        private object _run(Tensor fetches, Dictionary<Tensor, NDArray> feed_dict = null)
         {
             var feed_dict_tensor = new Dictionary<Tensor, NDArray>();
 
diff --git a/src/TensorFlowNET.Core/Tensors/Tensor.Operators.cs b/src/TensorFlowNET.Core/Tensors/Tensor.Operators.cs
index 2653a9e0..f2ac09fc 100644
--- a/src/TensorFlowNET.Core/Tensors/Tensor.Operators.cs
+++ b/src/TensorFlowNET.Core/Tensors/Tensor.Operators.cs
@@ -11,6 +11,11 @@ namespace Tensorflow
             return gen_math_ops.add(t1, t2);
         }
 
+        public static Tensor operator -(Tensor t1, Tensor t2)
+        {
+            return gen_math_ops.sub(t1, t2);
+        }
+
         public static Tensor operator *(Tensor t1, Tensor t2)
         {
             return gen_math_ops.mul(t1, t2);
diff --git a/src/TensorFlowNET.Core/Tensors/Tensor.cs b/src/TensorFlowNET.Core/Tensors/Tensor.cs
index 4281e7f8..dd37c8b2 100644
--- a/src/TensorFlowNET.Core/Tensors/Tensor.cs
+++ b/src/TensorFlowNET.Core/Tensors/Tensor.cs
@@ -211,6 +211,11 @@ namespace Tensorflow
             status.Dispose();
         }
 
+        public static implicit operator Tensor(int scalar)
+        {
+            return new Tensor(scalar);
+        }
+
         public static implicit operator IntPtr(Tensor tensor)
         {
             return tensor._handle;
@@ -220,5 +225,10 @@ namespace Tensorflow
         {
             return new Tensor(handle);
         }
+
+        public static implicit operator Tensor(RefVariable var)
+        {
+            return var._initial_value;
+        }
     }
 }
diff --git a/test/TensorFlowNET.Examples/LinearRegression.cs b/test/TensorFlowNET.Examples/LinearRegression.cs
index 633d7b82..3199a923 100644
--- a/test/TensorFlowNET.Examples/LinearRegression.cs
+++ b/test/TensorFlowNET.Examples/LinearRegression.cs
@@ -40,7 +40,8 @@ namespace TensorFlowNET.Examples
             var pred = tf.add(part1, b);
 
             // Mean squared error
-            var cost = tf.reduce_sum(tf.pow(pred - Y, 2)) / (2 * n_samples);
+            var pow = tf.pow(pred - Y, 2);
+            //var cost = tf.reduce_sum(pow) / (2 * n_samples);
         }
     }
 }