diff --git a/poincare/include/poincare/rational.h b/poincare/include/poincare/rational.h
index 0f868f02d..9676bb0e4 100644
--- a/poincare/include/poincare/rational.h
+++ b/poincare/include/poincare/rational.h
@@ -17,7 +17,7 @@ public:
   Rational(Integer::native_int_t i, Integer::native_int_t j) : Rational(Integer(i), Integer(j)) {}
 
   Rational(const Rational & other);
-
+  Rational & operator=(const Rational & other);
   // Getter
   const Integer numerator() const;
   const Integer denominator() const;
diff --git a/poincare/src/binomial_coefficient.cpp b/poincare/src/binomial_coefficient.cpp
index a6a39f5b0..231a6ded0 100644
--- a/poincare/src/binomial_coefficient.cpp
+++ b/poincare/src/binomial_coefficient.cpp
@@ -55,7 +55,7 @@ Expression * BinomialCoefficient::shallowReduce(Context& context, AngleUnit angl
   if (n.isLowerThan(k)) {
     return replaceWith(new Undefined(), true);
   }
-  Integer result(1);
+  Rational result(1);
   Integer kBis = Integer::Subtraction(n, k);
   k = kBis.isLowerThan(k) ? kBis : k;
   // Out of bounds
@@ -64,8 +64,8 @@ Expression * BinomialCoefficient::shallowReduce(Context& context, AngleUnit angl
   }
   int clippedK = k.extractedInt(); // Authorized because k < k_maxNumberOfSteps
   for (int i = 0; i < clippedK; i++) {
-    Integer factor = Integer::Division(Integer::Subtraction(n, Integer(i)), Integer::Subtraction(k, Integer(i))).quotient;
-    result = Integer::Multiplication(result, factor);
+    Rational factor = Rational(Integer::Subtraction(n, Integer(i)), Integer::Subtraction(k, Integer(i)));
+    result = Rational::Multiplication(result, factor);
   }
   return replaceWith(new Rational(result), true);
 }
diff --git a/poincare/src/rational.cpp b/poincare/src/rational.cpp
index d1fd32ee1..0a86f41d9 100644
--- a/poincare/src/rational.cpp
+++ b/poincare/src/rational.cpp
@@ -45,6 +45,13 @@ Rational::Rational(const Rational & other) {
   m_denominator = other.m_denominator;
 }
 
+Rational & Rational::operator=(const Rational & other) {
+  m_numerator = other.m_numerator;
+  m_numerator = other.m_numerator;
+  m_denominator = other.m_denominator;
+  return *this;
+}
+
 // Getter
 const Integer Rational::numerator() const {
   return m_numerator;
diff --git a/poincare/test/simplify_easy.cpp b/poincare/test/simplify_easy.cpp
index 59e44219e..75a5138fd 100644
--- a/poincare/test/simplify_easy.cpp
+++ b/poincare/test/simplify_easy.cpp
@@ -61,6 +61,9 @@ QUIZ_CASE(poincare_simplify_easy) {
   assert_parsed_expression_simplify_to("asin([[1/R(2),1/2][1,-1]])", "[[P/4,P/6][P/2,-P/2]]");
   assert_parsed_expression_simplify_to("atan([[R(3),1][1/R(3),-1]])", "[[P/3,P/4][P/6,-P/4]]");
   assert_parsed_expression_simplify_to("acos([[1/R(2),1/2][1,-1]])", "[[P/4,P/3][0,P]]");
+  assert_parsed_expression_simplify_to("binomial([[1,-2][3,4]], 2)", "undef");
+  assert_parsed_expression_simplify_to("binomial(20,3)", "1140");
+  assert_parsed_expression_simplify_to("binomial(20,10)", "184756");
 
   assert_parsed_expression_simplify_to("1*tan(2)*tan(5)", "tan(2)*tan(5)");
   assert_parsed_expression_simplify_to("P+(3R(2)-2R(3))/25", "(3R(2)-2R(3)+25P)/25");