diff --git a/exercice_2/src/compute_arithmetic.cc b/exercice_2/src/compute_arithmetic.cc
index 51f4c7b..491931e 100644
--- a/exercice_2/src/compute_arithmetic.cc
+++ b/exercice_2/src/compute_arithmetic.cc
@@ -1,4 +1,12 @@
 #include "compute_arithmetic.hh"
 /* -------------------------------------------------------------------------- */
 
 double ComputeArithmetic::computeTerm(unsigned int k) { return 1. * k; }
+
+double ComputeArithmetic::compute(unsigned int N) {
+  int s = 0;
+  for (int i = 0; i < N; ++i)
+    s += this->computeTerm(i);
+
+  return s;
+}
diff --git a/exercice_2/src/compute_arithmetic.hh b/exercice_2/src/compute_arithmetic.hh
index 45869dd..8f031c6 100644
--- a/exercice_2/src/compute_arithmetic.hh
+++ b/exercice_2/src/compute_arithmetic.hh
@@ -1,16 +1,17 @@
 #ifndef COMPUTE_ARITHMETIC_HH
 #define COMPUTE_ARITHMETIC_HH
 
 #include "series.hh"
 
 class ComputeArithmetic : public Series {
 
 public:
   ComputeArithmetic();
   virtual ~ComputeArithmetic();
 
 public:
   double computeTerm(unsigned int k) override;
+  double compute(unsigned int N) override;
 };
 
 #endif
diff --git a/exercice_2/src/series.cc b/exercice_2/src/series.cc
index 2d77f4b..07ca44d 100644
--- a/exercice_2/src/series.cc
+++ b/exercice_2/src/series.cc
@@ -1,25 +1,24 @@
 #include "series.hh"
 
-Series::Series() {
-  current_term = 0;
-  current_value = 0;
-}
+// Series::Series() {
+//   current_term = 0;
+//   current_value = 0;
+// }
 
-double Series::compute(unsigned int N) {
-  if (this->current_term <= N) {
-    N -= this->current_term;
-  } else {
-    this->current_term = 0;
-    this->current_value = 0.0;
-  }
-  for (int k = 0; k < N; ++k) {
-    addTerm();
-    return this->current_value;
-  }
-}
+// double Series::compute(unsigned int N) {
+//   if (this->current_term <= N) {
+//     N -= this->current_term;
+//   } else {
+//     this->current_term = 0;
+//     this->current_value = 0.0;
+//   }
+//   for (int k = 0; k < N; ++k) {
+//     addTerm();
+//     return this->current_value;
+//   }
+// }
 
-void Series::addTerm() {
-
-  this->current_term += 1;
-  this->current_value += this->computeTerm(this->current_term);
-}
+// void Series::addTerm() {
+//   this->current_term += 1;
+//   this->current_value += this->computeTerm(this->current_term);
+// }