diff --git a/samigo/samigo-app/src/java/org/sakaiproject/tool/assessment/bundle/AuthorMessages.properties b/samigo/samigo-app/src/java/org/sakaiproject/tool/assessment/bundle/AuthorMessages.properties
index fb6f23874a0e..70f7e263ad3d 100644
--- a/samigo/samigo-app/src/java/org/sakaiproject/tool/assessment/bundle/AuthorMessages.properties
+++ b/samigo/samigo-app/src/java/org/sakaiproject/tool/assessment/bundle/AuthorMessages.properties
@@ -180,6 +180,7 @@ invalid_min_scale=Min decimal places greater than scale value
 invalid_max=Max must be a valid number (0.0)
 invalid_max_scale=Max decimal places greater than scale value
 unique_names=Variables, Global Variables and Formulas must have unique names
+repeated_formula_names_instructions=There are repeated names on formulas {{ }} in the instructions
 variable_name_empty=Variable name cannot be empty.  Variables must begin with an alpha character and can only contain alpha, numeric, and underscore characters and are wrapped in single curly braces (i.e. {x} )
 variable_name_invalid=Variable name is invalid.  Variables must begin with an alpha character and can only contain alpha, numeric, and underscore characters and are wrapped in single curly braces (i.e. {x} )
 formula_name_empty=Formula name cannot be empty.  Formula names must begin with an alpha character and can only contain alpha, numeric, and underscore characters and are wrapped in double curly braces (i.e. {{y}} )
diff --git a/samigo/samigo-app/src/java/org/sakaiproject/tool/assessment/bundle/AuthorMessages_es.properties b/samigo/samigo-app/src/java/org/sakaiproject/tool/assessment/bundle/AuthorMessages_es.properties
index 8350b11880ec..3c12b41136f5 100644
--- a/samigo/samigo-app/src/java/org/sakaiproject/tool/assessment/bundle/AuthorMessages_es.properties
+++ b/samigo/samigo-app/src/java/org/sakaiproject/tool/assessment/bundle/AuthorMessages_es.properties
@@ -181,7 +181,7 @@ invalid_min_scale=El n\u00famero de decimales m\u00ednimo supera la escala
 invalid_max=Max debe ser un n\u00famero v\u00e1lido (0.0)
 invalid_max_scale=El n\u00famero de decimales m\u00e1ximo supera la escala
 unique_names=Las variables, las variables globales y las f\u00f3rmulas deben tener nombres exclusivos
-
+repeated_formula_names_instructions=No puede haber nombres repetidos en las formulas {{ }} de las instrucciones
 variable_name_empty=El nombre de la variable no puede estar vac\u00edo. Las variables deben comenzar con un car\u00e1cter alfab\u00e9tico (no num\u00e9rico) y s\u00f3lo pueden contener caracteres alfanum\u00e9ricos y guiones bajos y deben estar envueltas en llaves individuales (por ejemplo, {x})
 variable_name_invalid=El nombre de la variable no es v\u00e1lido. Las variables deben comenzar con un car\u00e1cter alfab\u00e9tico y s\u00f3lo pueden contener caracteres alfanum\u00e9ricos y guiones bajos y deben estar envueltas en llaves individuales (por ejemplo, {x})
 formula_name_invalid=El nombre de la f\u00f3rmula no es v\u00e1lido. Los nombres de f\u00f3rmula deben comenzar con un car\u00e1cter alfab\u00e9tico y s\u00f3lo pueden contener caracteres alfanum\u00e9ricos, y guiones bajos y deben estar envueltas en llaves dobles (por ejemplo, {{y}})
diff --git a/samigo/samigo-app/src/java/org/sakaiproject/tool/assessment/ui/listener/author/CalculatedQuestionExtractListener.java b/samigo/samigo-app/src/java/org/sakaiproject/tool/assessment/ui/listener/author/CalculatedQuestionExtractListener.java
index c65c847a0332..71e558838c85 100644
--- a/samigo/samigo-app/src/java/org/sakaiproject/tool/assessment/ui/listener/author/CalculatedQuestionExtractListener.java
+++ b/samigo/samigo-app/src/java/org/sakaiproject/tool/assessment/ui/listener/author/CalculatedQuestionExtractListener.java
@@ -27,6 +27,7 @@
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
@@ -136,6 +137,9 @@ public List<String> validate(ItemBean item,boolean extracting) {
         errors.addAll(validateExtractedNames(corrvariableNames, corrformulaNames, globalVariableNames));
         errors.addAll(validateExtractedNames(incorrvariableNames, incorrformulaNames, globalVariableNames));
 
+        //checking if there are duplicated formula names on instructions.
+        errors.addAll(checkDuplicatesFormulaNamesOnInstructions(formulaNames));
+
         // checking if there are variable names on feedback which are not in instructions.
         errors.addAll(checkVariableNamesOnFeedback(variableNames, corrvariableNames, VARIABLE_ON_CORRECT_FEEDBACK_NOT_IN_INSTRUCTIONS));
         errors.addAll(checkVariableNamesOnFeedback(variableNames, incorrvariableNames, VARIABLE_ON_INCORRECT_FEEDBACK_NOT_IN_INSTRUCTIONS));
@@ -853,4 +857,20 @@ private static List<String> checkGlobalVariableNamesFeedabackOnGlobalVariables(M
         return errors;
     }
 
+    /**
+     * checkDuplicatesFormulaNamesOnInstructions() check if there are duplicated formula names
+     * @param formulasNames
+     * @return
+     */
+    private static List<String> checkDuplicatesFormulaNamesOnInstructions(List<String> formulasNames) {
+        List<String> errors = new ArrayList<String>();
+
+        HashSet<String> set = new HashSet<>(formulasNames);
+        if (set.size() < formulasNames.size()) {
+            errors.add(getErrorMessage("repeated_formula_names_instructions"));
+        }
+
+        return errors;
+    }
+
 }