diff --git a/apps/calculation/calculation.cpp b/apps/calculation/calculation.cpp
index 3768abd89..d64202749 100644
--- a/apps/calculation/calculation.cpp
+++ b/apps/calculation/calculation.cpp
@@ -71,8 +71,7 @@ void Calculation::setContent(const char * c, Context * context, CalculationStore
   /* We do not store directly the text enter by the user but its serialization
    * to be able to compare it to the exact ouput text. */
   m_input->writeTextInBuffer(m_inputText, sizeof(m_inputText));
-  m_exactOutput = input()->clone();
-  Expression::Simplify(&m_exactOutput, *context);
+  m_exactOutput = Expression::ParseAndSimplify(m_inputText, *context);
   m_exactOutput->writeTextInBuffer(m_exactOutputText, sizeof(m_exactOutputText));
   m_approximateOutput = m_exactOutput->approximate<double>(*context);
   m_approximateOutput->writeTextInBuffer(m_approximateOutputText, sizeof(m_approximateOutputText));
@@ -148,13 +147,8 @@ void Calculation::tidy() {
 Expression * Calculation::exactOutput(Context * context) {
   if (m_exactOutput == nullptr) {
     /* To ensure that the expression 'm_exactOutput' is a simplified, we
-     * call 'simplifyAndBeautify'. */
-    m_exactOutput = Expression::parse(m_exactOutputText);
-    if (m_exactOutput != nullptr) {
-      Expression::Simplify(&m_exactOutput, *context);
-    } else {
-      m_exactOutput = new Undefined();
-    }
+     * call 'ParseAndSimplify'. */
+    m_exactOutput = Expression::ParseAndSimplify(m_exactOutputText, *context);
   }
   return m_exactOutput;
 }
diff --git a/apps/sequence/sequence.cpp b/apps/sequence/sequence.cpp
index 6658dbc0a..b0bfe3ae2 100644
--- a/apps/sequence/sequence.cpp
+++ b/apps/sequence/sequence.cpp
@@ -149,20 +149,14 @@ void Sequence::setInitialRank(int rank) {
 
 Poincare::Expression * Sequence::firstInitialConditionExpression(Context * context) const {
   if (m_firstInitialConditionExpression == nullptr) {
-    m_firstInitialConditionExpression = Poincare::Expression::parse(m_firstInitialConditionText);
-    if (m_firstInitialConditionExpression) {
-      Expression::Simplify(&m_firstInitialConditionExpression, *context);
-    }
+    m_firstInitialConditionExpression = Poincare::Expression::ParseAndSimplify(m_firstInitialConditionText, *context);
   }
   return m_firstInitialConditionExpression;
 }
 
 Poincare::Expression * Sequence::secondInitialConditionExpression(Context * context) const {
   if (m_secondInitialConditionExpression == nullptr) {
-    m_secondInitialConditionExpression = Poincare::Expression::parse(m_secondInitialConditionText);
-    if (m_secondInitialConditionExpression) {
-      Expression::Simplify(&m_secondInitialConditionExpression, *context);
-    }
+    m_secondInitialConditionExpression = Poincare::Expression::ParseAndSimplify(m_secondInitialConditionText, *context);
   }
   return m_secondInitialConditionExpression;
 }
diff --git a/apps/shared/function.cpp b/apps/shared/function.cpp
index dd4e46444..2c36c64cc 100644
--- a/apps/shared/function.cpp
+++ b/apps/shared/function.cpp
@@ -71,10 +71,7 @@ const char * Function::name() const {
 
 Poincare::Expression * Function::expression(Poincare::Context * context) const {
   if (m_expression == nullptr) {
-    m_expression = Expression::parse(m_text);
-    if (m_expression) {
-      Expression::Simplify(&m_expression, *context);
-    }
+    m_expression = Expression::ParseAndSimplify(m_text, *context);
   }
   return m_expression;
 }
diff --git a/poincare/include/poincare/expression.h b/poincare/include/poincare/expression.h
index 87b5b4987..44dd1cb89 100644
--- a/poincare/include/poincare/expression.h
+++ b/poincare/include/poincare/expression.h
@@ -217,6 +217,7 @@ public:
   virtual int writeTextInBuffer(char * buffer, int bufferSize) const = 0;
 
   /* Simplification */
+  static Expression * ParseAndSimplify(const char * text, Context & context, AngleUnit angleUnit = AngleUnit::Default);
   static void Simplify(Expression ** expressionAddress, Context & context, AngleUnit angleUnit = AngleUnit::Default);
 
   /* Evaluation Engine
diff --git a/poincare/src/expression.cpp b/poincare/src/expression.cpp
index 120d674c6..5116d63df 100644
--- a/poincare/src/expression.cpp
+++ b/poincare/src/expression.cpp
@@ -56,6 +56,7 @@ Expression * Expression::replaceSymbolWithExpression(char symbol, Expression * e
 /* Circuit breaker */
 
 static Expression::CircuitBreaker sCircuitBreaker = nullptr;
+static bool sSimplificationHasBeenInterrupted = false;
 
 void Expression::setCircuitBreaker(CircuitBreaker cb) {
   sCircuitBreaker = cb;
@@ -65,7 +66,11 @@ bool Expression::shouldStopProcessing() {
   if (sCircuitBreaker == nullptr) {
     return false;
   }
-  return sCircuitBreaker();
+  if (sCircuitBreaker()) {
+    sSimplificationHasBeenInterrupted = true;
+    return true;
+  }
+  return false;
 }
 
 /* Hierarchy */
@@ -229,7 +234,20 @@ ExpressionLayout * Expression::createLayout(FloatDisplayMode floatDisplayMode, C
 
 /* Simplification */
 
+Expression * Expression::ParseAndSimplify(const char * text, Context & context, AngleUnit angleUnit) {
+  Expression * exp = parse(text);
+  if (exp == nullptr) {
+    return new Undefined();
+  }
+  Simplify(&exp, context, angleUnit);
+  if (exp == nullptr) {
+    return parse(text);
+  }
+  return exp;
+}
+
 void Expression::Simplify(Expression ** expressionAddress, Context & context, AngleUnit angleUnit) {
+  sSimplificationHasBeenInterrupted = false;
   if (angleUnit == AngleUnit::Default) {
     angleUnit = Preferences::sharedPreferences()->angleUnit();
   }
@@ -243,6 +261,11 @@ void Expression::Simplify(Expression ** expressionAddress, Context & context, An
   root.editableOperand(0)->deepReduce(context, angleUnit);
   root.editableOperand(0)->deepBeautify(context, angleUnit);
   *expressionAddress = root.editableOperand(0);
+  if (sSimplificationHasBeenInterrupted) {
+    root.detachOperands();
+    delete *expressionAddress;
+    *expressionAddress = nullptr;
+  }
 }
 
 
@@ -310,8 +333,7 @@ template<typename T> T Expression::approximateToScalar(Context& context, AngleUn
 }
 
 template<typename T> T Expression::approximateToScalar(const char * text, Context& context, AngleUnit angleUnit) {
-  Expression * exp = parse(text);
-  Simplify(&exp, context, angleUnit);
+  Expression * exp = ParseAndSimplify(text, context, angleUnit);
   T result = exp->approximateToScalar<T>(context, angleUnit);
   delete exp;
   return result;