diff --git a/poincare/include/poincare/commutative_operation.h b/poincare/include/poincare/commutative_operation.h
index e7e01f8d1..d38a6103d 100644
--- a/poincare/include/poincare/commutative_operation.h
+++ b/poincare/include/poincare/commutative_operation.h
@@ -11,6 +11,7 @@ class CommutativeOperation : public Expression {
     int numberOfOperands() override;
     float approximate(Context& context) override;
     ExpressionLayout * createLayout() override;
+    bool isCommutative() override;
   protected:
     virtual float operateApproximatevelyOn(float a, float b) = 0;
     virtual char operatorChar() = 0;
diff --git a/poincare/include/poincare/expression.h b/poincare/include/poincare/expression.h
index e24680b3c..9a08d7cf8 100644
--- a/poincare/include/poincare/expression.h
+++ b/poincare/include/poincare/expression.h
@@ -40,6 +40,7 @@ class Expression {
     Expression * simplify();
 
     virtual Type type() = 0;
+    virtual bool isCommutative();
 
     virtual float approximate(Context& context) = 0;
 };
diff --git a/poincare/src/commutative_operation.cpp b/poincare/src/commutative_operation.cpp
index f96c76f90..8ce561859 100644
--- a/poincare/src/commutative_operation.cpp
+++ b/poincare/src/commutative_operation.cpp
@@ -57,3 +57,8 @@ ExpressionLayout * CommutativeOperation::createLayout() {
   }
   return new HorizontalLayout(children_layouts, number_of_children);
 }
+
+bool CommutativeOperation::isCommutative() {
+  return true;
+}
+
diff --git a/poincare/src/expression.cpp b/poincare/src/expression.cpp
index cb7f19f94..0b24d46b1 100644
--- a/poincare/src/expression.cpp
+++ b/poincare/src/expression.cpp
@@ -63,3 +63,7 @@ bool Expression::valueEquals(Expression * e) {
    * -riden. */
   return true;
 }
+
+bool Expression::isCommutative() {
+  return false;
+}