diff --git a/apps/calculation/calculation.cpp b/apps/calculation/calculation.cpp
index 98469c185..2c8827cf9 100644
--- a/apps/calculation/calculation.cpp
+++ b/apps/calculation/calculation.cpp
@@ -192,13 +192,14 @@ bool Calculation::shouldDisplayApproximateOutput(Context * context) {
   return input()->isApproximate(*context);
 }
 
-bool Calculation::exactAndApproximateOutputsAreEqual(Poincare::Context * context) {
-  if (exactOutput(context)->type() != Expression::Type::Rational) {
-    return false;
-  }
-  assert(approximateOutput(context)->type() == Type::Complex);
+bool Calculation::exactAndApproximateDisplayedOutputsAreEqual(Poincare::Context * context) {
   char buffer[k_printedExpressionSize];
-  Complex<double>::convertFloatToText(static_cast<Complex<double> *>(approximateOutput(context))->a(), buffer, k_printedExpressionSize, Preferences::sharedPreferences()->numberOfSignificantDigits(), Preferences::sharedPreferences()->displayMode());
+  approximateOutput(context)->writeTextInBuffer(buffer, k_printedExpressionSize, Preferences::sharedPreferences()->numberOfSignificantDigits());
+  /* Warning: we cannot use directly the m_approximateOutputText but we have to
+   * re-serialize the approximateOutput because the number of stored
+   * significative numbers and the number of displayed significative numbers
+   * are not identical. (For example, 0.000025 might be displayed "0.00003"
+   * which requires in an approximative equal) */
   Expression * approximateOutput = Expression::ParseAndSimplify(buffer, *context);
   bool isEqual = approximateOutput->isIdenticalTo(exactOutput(context));
   delete approximateOutput;
diff --git a/apps/calculation/calculation.h b/apps/calculation/calculation.h
index ce28f55d3..eaf4c6234 100644
--- a/apps/calculation/calculation.h
+++ b/apps/calculation/calculation.h
@@ -31,7 +31,7 @@ public:
   bool isEmpty();
   void tidy();
   bool shouldDisplayApproximateOutput(Poincare::Context * context);
-  bool exactAndApproximateOutputsAreEqual(Poincare::Context * context);
+  bool exactAndApproximateDisplayedOutputsAreEqual(Poincare::Context * context);
   constexpr static int k_printedExpressionSize = 2*::TextField::maxBufferSize();
 private:
   /* Buffers holding text expressions have to be longer than the text written
diff --git a/apps/calculation/history_view_cell.cpp b/apps/calculation/history_view_cell.cpp
index 2193d6f20..a1f6881ee 100644
--- a/apps/calculation/history_view_cell.cpp
+++ b/apps/calculation/history_view_cell.cpp
@@ -90,7 +90,7 @@ void HistoryViewCell::setCalculation(Calculation * calculation) {
    * outputView()->layoutSubviews() is going to fail. */
   Poincare::ExpressionLayout * outputExpressions[2] = {calculation->approximateOutputLayout(calculationApp->localContext()), calculation->shouldDisplayApproximateOutput(calculationApp->localContext()) ? nullptr : calculation->exactOutputLayout(calculationApp->localContext())};
   m_scrollableOutputView.outputView()->setExpressions(outputExpressions);
-  I18n::Message equalMessage = calculation->exactAndApproximateOutputsAreEqual(calculationApp->localContext()) ? I18n::Message::Equal : I18n::Message::AlmostEqual;
+  I18n::Message equalMessage = calculation->exactAndApproximateDisplayedOutputsAreEqual(calculationApp->localContext()) ? I18n::Message::Equal : I18n::Message::AlmostEqual;
   m_scrollableOutputView.outputView()->setEqualMessage(equalMessage);
 }