diff --git a/poincare/include/poincare/addition.h b/poincare/include/poincare/addition.h
index 1450d2edc..f3315305d 100644
--- a/poincare/include/poincare/addition.h
+++ b/poincare/include/poincare/addition.h
@@ -6,8 +6,9 @@
 class Addition : public Expression {
   public:
     Addition(Expression * first_operand, Expression * second_operand);
+    ~Addition();
     ExpressionLayout * createLayout(ExpressionLayout * parent) override;
-    virtual float approximate();
+    float approximate() override;
   private:
     Expression * m_children[2];
 };
diff --git a/poincare/include/poincare/expression.h b/poincare/include/poincare/expression.h
index 7980c8be3..1e587df70 100644
--- a/poincare/include/poincare/expression.h
+++ b/poincare/include/poincare/expression.h
@@ -7,6 +7,7 @@
 class Expression {
   public:
     static Expression * parse(char * string);
+    virtual ~Expression();
 
     //virtual Expression ** children() = 0; // NULL-terminated
 
diff --git a/poincare/include/poincare/fraction.h b/poincare/include/poincare/fraction.h
index ff7b6f2e6..50d21a9d9 100644
--- a/poincare/include/poincare/fraction.h
+++ b/poincare/include/poincare/fraction.h
@@ -6,12 +6,12 @@
 class Fraction : public Expression {
   public:
     Fraction(Expression * numerator, Expression * denominator);
-//    virtual Expression ** children();
-//  protected:
-    virtual ExpressionLayout * createLayout(ExpressionLayout * parent);
-    virtual float approximate();
+    ~Fraction();
+    ExpressionLayout * createLayout(ExpressionLayout * parent) override;
+    float approximate() override;
   private:
-    Expression * m_children[3];
+    Expression * m_numerator;
+    Expression * m_denominator;
 };
 
 #endif
diff --git a/poincare/src/addition.cpp b/poincare/src/addition.cpp
index 75ee79d82..1e68ff523 100644
--- a/poincare/src/addition.cpp
+++ b/poincare/src/addition.cpp
@@ -6,6 +6,11 @@ Addition::Addition(Expression * first_operand, Expression * second_operand) {
   m_children[1] = second_operand;
 }
 
+Addition::~Addition() {
+  delete m_children[1];
+  delete m_children[0];
+}
+
 float Addition::approximate() {
   return m_children[0]->approximate() + m_children[1]->approximate();
 }
diff --git a/poincare/src/expression.cpp b/poincare/src/expression.cpp
index 25ea59935..36069ed12 100644
--- a/poincare/src/expression.cpp
+++ b/poincare/src/expression.cpp
@@ -12,13 +12,15 @@ Expression * Expression::parse(char * string) {
   Expression * expression = 0;
   poincare_expression_yyparse(scanner, &expression);
 
-
   poincare_expression_yy_delete_buffer(buf, scanner);
   poincare_expression_yylex_destroy(scanner);
 
   return expression;
 }
 
+Expression::~Expression() {
+}
+
 /*
 bool Expression::identicalTo(Expression * e) {
   // By default, two expression are not identical.
diff --git a/poincare/src/fraction.cpp b/poincare/src/fraction.cpp
index 1e634748f..64798dcdb 100644
--- a/poincare/src/fraction.cpp
+++ b/poincare/src/fraction.cpp
@@ -2,62 +2,21 @@
 #include <string.h>
 #include "layout/fraction_layout.h"
 
-/*
-static inline KDCoordinate max(KDCoordinate a, KDCoordinate b) {
-  return (a > b ? a : b);
+Fraction::Fraction(Expression * numerator, Expression * denominator) :
+  m_numerator(numerator),
+  m_denominator(denominator) {
 }
-*/
 
-#define NUMERATOR m_children[0]
-#define DENOMINATOR m_children[1]
-
-#define FRACTION_BORDER_LENGTH 2
-#define FRACTION_LINE_MARGIN 2
-#define FRACTION_LINE_HEIGHT 1
-
-Fraction::Fraction(Expression * numerator, Expression * denominator) {
-  m_children[0] = numerator;
-  m_children[1] = denominator;
-  m_children[2] = NULL;
+Fraction::~Fraction() {
+  delete m_denominator;
+  delete m_numerator;
 }
-/*
-
-Expression ** Fraction::children() {
-  return m_children;
-}
-*/
 
 ExpressionLayout * Fraction::createLayout(ExpressionLayout * parent) {
-  return new FractionLayout(parent, NUMERATOR, DENOMINATOR);
+  return new FractionLayout(parent, m_numerator, m_denominator);
 }
-/*
-void Fraction::layout() {
-  KDRect numFrame = NUMERATOR->m_frame;
-  KDRect denFrame = DENOMINATOR->m_frame;
-
-  m_frame.width = max(numFrame.width, denFrame.width) + 2*FRACTION_BORDER_LENGTH;
-  m_frame.height = numFrame.height + FRACTION_LINE_MARGIN + FRACTION_LINE_HEIGHT + FRACTION_LINE_MARGIN + denFrame.height;
-
-  NUMERATOR->m_frame.origin = {
-    .x = (KDCoordinate)((m_frame.width - numFrame.width)/2),
-    .y = 0
-  };
-
-  DENOMINATOR->m_frame.origin = {
-    .x = (KDCoordinate)((m_frame.width - denFrame.width)/2),
-    .y = (KDCoordinate)(numFrame.height + 2*FRACTION_LINE_MARGIN + FRACTION_LINE_HEIGHT)
-  };
-}
-
-void Fraction::draw() {
-  KDCoordinate fractionLineY = NUMERATOR->m_frame.height + FRACTION_LINE_MARGIN;
-
-  KDDrawLine((KDPoint){.x = 0, .y = fractionLineY},
-      (KDPoint){.x = m_frame.width, .y = fractionLineY});
-}
-*/
 
 float Fraction::approximate() {
   // TODO: handle division by zero
-  return m_children[0]->approximate()/m_children[1]->approximate();
+  return m_numerator->approximate()/m_denominator->approximate();
 }