diff --git a/poincare/src/addition.cpp b/poincare/src/addition.cpp
index 9db97c40d..501a57a10 100644
--- a/poincare/src/addition.cpp
+++ b/poincare/src/addition.cpp
@@ -143,7 +143,10 @@ Expression Addition::shallowReduce(ExpressionNode::ReductionContext reductionCon
   }
 
   /* Step 1: Addition is associative, so let's start by merging children which
-   * are additions. */
+   * are additions.
+   * TODO If the parent Expression is an Addition, one should perhaps
+   * return now and let the parent do the reduction.
+   */
   mergeSameTypeChildrenInPlace();
 
   const int childrenCount = numberOfChildren();
diff --git a/poincare/src/multiplication.cpp b/poincare/src/multiplication.cpp
index 9a7fff846..e97e3b3ec 100644
--- a/poincare/src/multiplication.cpp
+++ b/poincare/src/multiplication.cpp
@@ -504,7 +504,10 @@ Expression Multiplication::privateShallowReduce(ExpressionNode::ReductionContext
   }
 
   /* Step 1: MultiplicationNode is associative, so let's start by merging children
-   * which also are multiplications themselves. */
+   * which also are multiplications themselves.
+   * TODO If the parent Expression is a Multiplication, one should perhaps
+   * return now and let the parent do the reduction.
+   */
   mergeSameTypeChildrenInPlace();
 
   Context * context = reductionContext.context();