diff --git a/example/formula_evaluation_example.dart b/example/formula_evaluation_example.dart
index 333a3ce..d629036 100644
--- a/example/formula_evaluation_example.dart
+++ b/example/formula_evaluation_example.dart
@@ -23,9 +23,7 @@ void main() {
     ],
     output:  VariableSpec(name: 'F', magnitude: 'force'),
     d4rtCode: '''
-      main() {
         return m * a;
-      }
     ''',
   );
   
@@ -57,9 +55,7 @@ void main() {
     ],
     output : VariableSpec(name: 'discriminant', magnitude: 'scalar'),
     d4rtCode: '''
-      main() {
         return b * b - 4 * a * c;
-      }
     ''',
   );
   
@@ -97,10 +93,8 @@ void main() {
     output: VariableSpec(name: 'A', magnitude: 'area'),
 
     d4rtCode: '''
-      main() {
         var pi = 3.14159265359;
         return pi * r * r;
-      }
     ''',
   );
   
@@ -144,7 +138,6 @@ void main() {
     ],
     output: VariableSpec(name: 'A', magnitude: 'currency'),      // Final amount
     d4rtCode: '''
-      main() {
         // A = P * (1 + r/n)^(n*t)
         var rate_per_period = r / n;
         var base = 1 + rate_per_period;
@@ -158,7 +151,6 @@ void main() {
         }
         
         return result;
-      }
     ''',
   );
   
diff --git a/lib/formula_evaluator.dart b/lib/formula_evaluator.dart
index 65e3a89..7a6be47 100644
--- a/lib/formula_evaluator.dart
+++ b/lib/formula_evaluator.dart
@@ -48,6 +48,8 @@ class FormulaEvaluator {
     try {
       // Build the complete d4rt source code with variable declarations
       final completeSource = _buildCompleteSource(formula, inputValues);
+      //print( "$formula");
+      //print( "$completeSource" );
       
       // Execute the code using d4rt (no args needed since variables are in source)
       final result = _interpreter.execute(source: completeSource);
@@ -99,7 +101,9 @@ class FormulaEvaluator {
   /// before the formula's d4rt code
   String _buildCompleteSource(Formula formula, Map<String, dynamic> inputValues) {
     final buffer = StringBuffer();
-    
+
+    buffer.writeln("main(){");
+
     // Add variable declarations for all input variables
     for (final entry in inputValues.entries) {
       final varName = entry.key;
@@ -121,6 +125,7 @@ class FormulaEvaluator {
     
     // Add the formula's d4rt code
     buffer.write(formula.d4rtCode);
+    buffer.write("}");
     
     return buffer.toString();
   }
diff --git a/test/formula_evaluator_test.dart b/test/formula_evaluator_test.dart
index 8988853..60625c5 100644
--- a/test/formula_evaluator_test.dart
+++ b/test/formula_evaluator_test.dart
@@ -20,9 +20,7 @@ void main() {
           ],
           output: VariableSpec(name: 'F', magnitude: 'force'),
           d4rtCode: '''
-            main() {
               return a * m;
-            }
           ''',
         );
 
@@ -43,9 +41,7 @@ void main() {
           ],
           output: VariableSpec(name: 'result', magnitude: 'scalar'),
           d4rtCode: '''
-            main() {
               return x + y;
-            }
           ''',
         );
 
@@ -60,9 +56,7 @@ void main() {
           input: [VariableSpec(name: 'n', magnitude: 'scalar')],
           output: VariableSpec(name: 'result', magnitude: 'scalar'),
           d4rtCode: '''
-            main() {
               return n * n;
-            }
           ''',
         );
 
@@ -80,9 +74,7 @@ void main() {
           ],
           output: VariableSpec(name: 'discriminant', magnitude: 'scalar'),
           d4rtCode: '''
-            main() {
               return b * b - 4 * a * c;
-            }
           ''',
         );
 
@@ -102,7 +94,7 @@ void main() {
             VariableSpec(name: 'b', magnitude: 'scalar'),
           ],
           output: VariableSpec(name: 'result', magnitude: 'scalar'),
-          d4rtCode: 'main() { return a + b + z; }',
+          d4rtCode: 'return a + b + z;',
         );
 
         final order = evaluator.getInputVariableOrder(formula);
@@ -119,10 +111,8 @@ void main() {
           ],
           output: VariableSpec(name: 'result', magnitude: 'scalar'),
           d4rtCode: '''
-            main() {
               // Variables: a=1, y=2, z=3
               return a * 100 + y * 10 + z;
-            }
           ''',
         );
 
@@ -142,7 +132,7 @@ void main() {
             VariableSpec(name: 'y', magnitude: 'scalar'),
           ],
           output: VariableSpec(name: 'result', magnitude: 'scalar'),
-          d4rtCode: 'main() { return x + y; }',
+          d4rtCode: 'return x + y;',
         );
 
         expect(
@@ -172,7 +162,7 @@ void main() {
           name: 'Test',
           input: [VariableSpec(name: 'x', magnitude: 'scalar')],
           output: VariableSpec(name: 'force', magnitude: 'Newton'),
-          d4rtCode: 'main() { return x; }',
+          d4rtCode: 'return x;',
         );
 
         expect(evaluator.getOutputVariableName(formula), 'force');
@@ -185,7 +175,7 @@ void main() {
             name: 'Test',
             input: [VariableSpec(name: 'x', magnitude: 'scalar')],
             output: VariableSpec(name: 'force', magnitude: 'Newton'),
-            d4rtCode: 'main() { return x; }',
+            d4rtCode: 'return x;',
           );
 
           expect(evaluator.getOutputVariableMagnitude(formula), 'Newton');
@@ -197,7 +187,7 @@ void main() {
           name: 'Valid Formula',
           input: [VariableSpec(name: 'x', magnitude: 'scalar')],
           output: VariableSpec(name: 'result', magnitude: 'Newton'),
-          d4rtCode: 'main() { return x; }',
+          d4rtCode: 'return x;',
         );
 
         expect(evaluator.getOutputVariableName(validFormula), 'result');
@@ -212,7 +202,7 @@ void main() {
           name: 'Integer test',
           input: [VariableSpec(name: 'n', magnitude: 'count')],
           output: VariableSpec(name: 'result', magnitude: 'count'),
-          d4rtCode: 'main() { return n + 1; }',
+          d4rtCode: 'return n + 1;',
         );
 
         final result = evaluator.evaluate(formula, {'n': 42});
@@ -224,7 +214,7 @@ void main() {
           name: 'Double test',
           input: [VariableSpec(name: 'x', magnitude: 'length')],
           output: VariableSpec(name: 'result', magnitude: 'area'),
-          d4rtCode: 'main() { return x * x; }',
+          d4rtCode: 'return x * x;',
         );
 
         final result = evaluator.evaluate(formula, {'x': 3.14});
diff --git a/test/pruebas_d4rt_test.dart b/test/pruebas_d4rt_test.dart
deleted file mode 100644
index 26ba701..0000000
--- a/test/pruebas_d4rt_test.dart
+++ /dev/null
@@ -1,7 +0,0 @@
-import 'package:test/test.dart';
-
-void main() {
-  test('calculate', () {
-    expect(6 * 7, 42);
-  });
-}