diff --git a/poincare/include/poincare/rational.h b/poincare/include/poincare/rational.h
index bfb296676..119d6b44b 100644
--- a/poincare/include/poincare/rational.h
+++ b/poincare/include/poincare/rational.h
@@ -16,6 +16,7 @@ public:
   Integer denominator() const;
   bool isNegative() const { return m_negative; }
   void setNegative(bool negative) { m_negative = negative; }
+  bool isInteger() const { return denominator().isOne(); }
 
   // TreeNode
   size_t size() const override;
@@ -43,11 +44,11 @@ public:
 
   // Basic test
   bool isZero() const { return unsignedNumerator().isZero(); }
-  bool isOne() const { return signedNumerator().isOne() && denominator().isOne(); }
-  bool isMinusOne() const { return signedNumerator().isMinusOne() && denominator().isOne(); }
+  bool isOne() const { return signedNumerator().isOne() && isInteger(); }
+  bool isMinusOne() const { return signedNumerator().isMinusOne() && isInteger(); }
   bool isHalf() const { return signedNumerator().isOne() && denominator().isTwo(); }
   bool isMinusHalf() const { return signedNumerator().isMinusOne() && denominator().isTwo(); }
-  bool isTen() const { return signedNumerator().isTen() && denominator().isOne(); }
+  bool isTen() const { return signedNumerator().isTen() && isInteger(); }
 
   static int NaturalOrder(const RationalNode * i, const RationalNode * j);
 private:
@@ -92,6 +93,7 @@ public:
   bool isMinusHalf() const { return node()->isMinusHalf(); }
   bool isTen() const { return node()->isTen(); }
   bool numeratorOrDenominatorIsInfinity() const;
+  bool isInteger() const { return node()->isInteger(); }
 
   // Arithmetic
   /* Warning: when using this function, always assert that the result does not
diff --git a/poincare/src/binomial_coefficient.cpp b/poincare/src/binomial_coefficient.cpp
index 51f83857d..9aa5d5af4 100644
--- a/poincare/src/binomial_coefficient.cpp
+++ b/poincare/src/binomial_coefficient.cpp
@@ -70,13 +70,13 @@ Expression BinomialCoefficient::shallowReduce(Context * context) {
 
   if (c0.type() == ExpressionNode::Type::Rational) {
     Rational r0 = static_cast<Rational&>(c0);
-    if (!r0.integerDenominator().isOne() || r0.isNegative()) {
+    if (!r0.isInteger() || r0.isNegative()) {
       return replaceWithUndefinedInPlace();
     }
   }
   if (c1.type() == ExpressionNode::Type::Rational) {
     Rational r1 = static_cast<Rational&>(c1);
-    if (!r1.integerDenominator().isOne() || r1.isNegative()) {
+    if (!r1.isInteger() || r1.isNegative()) {
       return replaceWithUndefinedInPlace();
     }
   }
diff --git a/poincare/src/confidence_interval.cpp b/poincare/src/confidence_interval.cpp
index 444d6ff9a..ffdf04e8d 100644
--- a/poincare/src/confidence_interval.cpp
+++ b/poincare/src/confidence_interval.cpp
@@ -72,7 +72,7 @@ Expression ConfidenceInterval::shallowReduce(ExpressionNode::ReductionContext re
   }
   if (c1.type() == ExpressionNode::Type::Rational) {
     Rational r1 = static_cast<Rational&>(c1);
-    if (!r1.integerDenominator().isOne() || r1.signedIntegerNumerator().isNegative()) {
+    if (!r1.isInteger() || r1.signedIntegerNumerator().isNegative()) {
       return replaceWithUndefinedInPlace();
     }
   }
diff --git a/poincare/src/division.cpp b/poincare/src/division.cpp
index c46da8b3e..843213dcd 100644
--- a/poincare/src/division.cpp
+++ b/poincare/src/division.cpp
@@ -32,7 +32,7 @@ bool DivisionNode::childNeedsSystemParenthesesAtSerialization(const TreeNode * c
   if (static_cast<const ExpressionNode *>(child)->isNumber() && Number(static_cast<const NumberNode *>(child)).sign() == Sign::Negative) {
     return true;
   }
-  if (static_cast<const ExpressionNode *>(child)->type() == Type::Rational && !static_cast<const RationalNode *>(child)->denominator().isOne()) {
+  if (static_cast<const ExpressionNode *>(child)->type() == Type::Rational && !static_cast<const RationalNode *>(child)->isInteger()) {
     return true;
   }
   Type types[] = {Type::Subtraction, Type::Opposite, Type::MultiplicationExplicite, Type::Division, Type::Addition};
diff --git a/poincare/src/division_quotient.cpp b/poincare/src/division_quotient.cpp
index 38ae2d252..14f41bab9 100644
--- a/poincare/src/division_quotient.cpp
+++ b/poincare/src/division_quotient.cpp
@@ -50,13 +50,13 @@ Expression DivisionQuotient::shallowReduce(Context * context) {
   }
   if (c0.type() == ExpressionNode::Type::Rational) {
     Rational r0 = static_cast<Rational &>(c0);
-    if (!r0.integerDenominator().isOne()) {
+    if (!r0.isInteger()) {
       return replaceWithUndefinedInPlace();
     }
   }
   if (c1.type() == ExpressionNode::Type::Rational) {
     Rational r1 = static_cast<Rational &>(c1);
-    if (!r1.integerDenominator().isOne()) {
+    if (!r1.isInteger()) {
       return replaceWithUndefinedInPlace();
     }
   }
diff --git a/poincare/src/division_remainder.cpp b/poincare/src/division_remainder.cpp
index 2cf4d826c..51c25f3a0 100644
--- a/poincare/src/division_remainder.cpp
+++ b/poincare/src/division_remainder.cpp
@@ -51,13 +51,13 @@ Expression DivisionRemainder::shallowReduce(Context * context) {
   }
   if (c0.type() == ExpressionNode::Type::Rational) {
     Rational r0 = static_cast<Rational &>(c0);
-    if (!r0.integerDenominator().isOne()) {
+    if (!r0.isInteger()) {
       return replaceWithUndefinedInPlace();
     }
   }
   if (c1.type() == ExpressionNode::Type::Rational) {
     Rational r1 = static_cast<Rational &>(c1);
-    if (!r1.integerDenominator().isOne()) {
+    if (!r1.isInteger()) {
       return replaceWithUndefinedInPlace();
     }
   }
diff --git a/poincare/src/factor.cpp b/poincare/src/factor.cpp
index a66aba309..99f6c75d1 100644
--- a/poincare/src/factor.cpp
+++ b/poincare/src/factor.cpp
@@ -87,7 +87,7 @@ Expression Factor::shallowBeautify(ExpressionNode::ReductionContext reductionCon
     return replaceWithUndefinedInPlace();
   }
   Expression result = numeratorDecomp.squashUnaryHierarchyInPlace();
-  if (!r.integerDenominator().isOne()) {
+  if (!r.isInteger()) {
     MultiplicationExplicite denominatorDecomp = createMultiplicationOfIntegerPrimeDecomposition(r.integerDenominator(), reductionContext.context(), reductionContext.complexFormat(), reductionContext.angleUnit());
     if (denominatorDecomp.numberOfChildren() == 0) {
       return replaceWithUndefinedInPlace();
diff --git a/poincare/src/factorial.cpp b/poincare/src/factorial.cpp
index f07eafc68..4c3ddc598 100644
--- a/poincare/src/factorial.cpp
+++ b/poincare/src/factorial.cpp
@@ -35,7 +35,7 @@ bool FactorialNode::childNeedsSystemParenthesesAtSerialization(const TreeNode *
    * --- ! ---> [2/3]!
    *  3
    */
-  if (static_cast<const ExpressionNode *>(child)->type() == Type::Rational && !static_cast<const RationalNode *>(child)->denominator().isOne()) {
+  if (static_cast<const ExpressionNode *>(child)->type() == Type::Rational && !static_cast<const RationalNode *>(child)->isInteger()) {
     return true;
   }
   Type types[] = {Type::Division, Type::Power};
@@ -100,7 +100,7 @@ Expression Factorial::shallowReduce(ExpressionNode::ReductionContext reductionCo
   }
   if (c.type() == ExpressionNode::Type::Rational) {
     Rational r = c.convert<Rational>();
-    if (!r.integerDenominator().isOne() || r.sign() == ExpressionNode::Sign::Negative) {
+    if (!r.isInteger() || r.sign() == ExpressionNode::Sign::Negative) {
       return replaceWithUndefinedInPlace();
     }
     if (Integer(k_maxOperandValue).isLowerThan(r.unsignedIntegerNumerator())) {
diff --git a/poincare/src/great_common_divisor.cpp b/poincare/src/great_common_divisor.cpp
index 26a03add2..93d7e9519 100644
--- a/poincare/src/great_common_divisor.cpp
+++ b/poincare/src/great_common_divisor.cpp
@@ -64,13 +64,13 @@ Expression GreatCommonDivisor::shallowReduce(Context * context) {
   }
   if (c0.type() == ExpressionNode::Type::Rational) {
     Rational r0 = static_cast<Rational &>(c0);
-    if (!r0.integerDenominator().isOne()) {
+    if (!r0.isInteger()) {
       return replaceWithUndefinedInPlace();
     }
   }
   if (c1.type() == ExpressionNode::Type::Rational) {
     Rational r1 = static_cast<Rational&>(c1);
-    if (!r1.integerDenominator().isOne()) {
+    if (!r1.isInteger()) {
       return replaceWithUndefinedInPlace();
     }
   }
diff --git a/poincare/src/least_common_multiple.cpp b/poincare/src/least_common_multiple.cpp
index 7dcfe1aa7..7109a5819 100644
--- a/poincare/src/least_common_multiple.cpp
+++ b/poincare/src/least_common_multiple.cpp
@@ -68,13 +68,13 @@ Expression LeastCommonMultiple::shallowReduce(Context * context) {
   }
   if (c0.type() == ExpressionNode::Type::Rational) {
     Rational r0 = static_cast<Rational &>(c0);
-    if (!r0.integerDenominator().isOne()) {
+    if (!r0.isInteger()) {
       return replaceWithUndefinedInPlace();
     }
   }
   if (c1.type() == ExpressionNode::Type::Rational) {
     Rational r1 = static_cast<Rational &>(c1);
-    if (!r1.integerDenominator().isOne()) {
+    if (!r1.isInteger()) {
       return replaceWithUndefinedInPlace();
     }
   }
diff --git a/poincare/src/logarithm.cpp b/poincare/src/logarithm.cpp
index 2ad55b28f..a348dbff3 100644
--- a/poincare/src/logarithm.cpp
+++ b/poincare/src/logarithm.cpp
@@ -196,7 +196,7 @@ Expression Logarithm::shallowReduce(ExpressionNode::ReductionContext reductionCo
     Rational r = static_cast<Rational &>(c);
     Addition a = Addition::Builder();
     // if the log base is Integer: log_b(r) = c + log_b(r') with r = b^c*r'
-    if (childAtIndex(1).type() == ExpressionNode::Type::Rational && childAtIndex(1).convert<Rational>().integerDenominator().isOne()) {
+    if (childAtIndex(1).type() == ExpressionNode::Type::Rational && childAtIndex(1).convert<Rational>().isInteger()) {
       Integer b = childAtIndex(1).convert<Rational>().signedIntegerNumerator();
       Integer newNumerator = simplifyLogarithmIntegerBaseInteger(r.signedIntegerNumerator(), b, a, false);
       Integer newDenomitor = simplifyLogarithmIntegerBaseInteger(r.integerDenominator(), b, a, true);
diff --git a/poincare/src/multiplication_explicite.cpp b/poincare/src/multiplication_explicite.cpp
index 26122e8ca..e9cda1ad5 100644
--- a/poincare/src/multiplication_explicite.cpp
+++ b/poincare/src/multiplication_explicite.cpp
@@ -537,8 +537,8 @@ void MultiplicationExplicite::addMissingFactors(Expression factor, Context * con
    * child, we replace it by its LCM with factor ; otherwise, we simply add
    * factor as a child. */
   if (numberOfChildren() > 0 && childAtIndex(0).type() == ExpressionNode::Type::Rational && factor.type() == ExpressionNode::Type::Rational) {
-    assert(static_cast<Rational &>(factor).integerDenominator().isOne());
-    assert(childAtIndex(0).convert<Rational>().integerDenominator().isOne());
+    assert(static_cast<Rational &>(factor).isInteger());
+    assert(childAtIndex(0).convert<Rational>().isInteger());
     Integer lcm = Arithmetic::LCM(static_cast<Rational &>(factor).unsignedIntegerNumerator(), childAtIndex(0).convert<Rational>().unsignedIntegerNumerator());
     if (lcm.isOverflow()) {
       addChildAtIndexInPlace(Rational::Builder(static_cast<Rational &>(factor).unsignedIntegerNumerator()), 1, numberOfChildren());
@@ -669,7 +669,7 @@ Expression MultiplicationExplicite::mergeNegativePower(Context * context, Prefer
    * for instance, a^(-1)*b^(-c)*c = c*(a*b^c)^(-1) */
   MultiplicationExplicite m = MultiplicationExplicite::Builder();
   // Special case for rational p/q: if q != 1, q should be at denominator
-  if (childAtIndex(0).type() == ExpressionNode::Type::Rational && !childAtIndex(0).convert<Rational>().integerDenominator().isOne()) {
+  if (childAtIndex(0).type() == ExpressionNode::Type::Rational && !childAtIndex(0).convert<Rational>().isInteger()) {
     Rational r = childAtIndex(0).convert<Rational>();
     m.addChildAtIndexInPlace(Rational::Builder(r.integerDenominator()), 0, m.numberOfChildren());
     if (r.signedIntegerNumerator().isOne()) {
diff --git a/poincare/src/multiplication_implicite.cpp b/poincare/src/multiplication_implicite.cpp
index fa553a3cd..2ccc3e5b1 100644
--- a/poincare/src/multiplication_implicite.cpp
+++ b/poincare/src/multiplication_implicite.cpp
@@ -26,7 +26,7 @@ bool MultiplicationImpliciteNode::childNeedsSystemParenthesesAtSerialization(con
    * ---i --> [2/3]i
    *  3
    */
-  if (static_cast<const ExpressionNode *>(child)->type() == Type::Rational && !static_cast<const RationalNode *>(child)->denominator().isOne()) {
+  if (static_cast<const ExpressionNode *>(child)->type() == Type::Rational && !static_cast<const RationalNode *>(child)->isInteger()) {
     return true;
   }
   // 2^{3}i --> [2^3]i
diff --git a/poincare/src/number.cpp b/poincare/src/number.cpp
index bd5c613af..ba8e8769a 100644
--- a/poincare/src/number.cpp
+++ b/poincare/src/number.cpp
@@ -110,7 +110,7 @@ Number Number::Power(const Number & i, const Number & j) {
   return BinaryOperation(i, j,
       // Special case for Rational^Rational: we escape to Float if the index is not an Integer
       [](const Rational & i, const Rational & j) {
-        if (!j.integerDenominator().isOne()) {
+        if (!j.isInteger()) {
           // We return an overflown result to reach the escape case Float+Float
           return Rational::Builder(Integer::Overflow(false));
         }
diff --git a/poincare/src/permute_coefficient.cpp b/poincare/src/permute_coefficient.cpp
index 5d9cc0317..1ff47a451 100644
--- a/poincare/src/permute_coefficient.cpp
+++ b/poincare/src/permute_coefficient.cpp
@@ -64,13 +64,13 @@ Expression PermuteCoefficient::shallowReduce(Context * context) {
   }
   if (c0.type() == ExpressionNode::Type::Rational) {
     Rational r0 = static_cast<Rational &>(c0);
-    if (!r0.integerDenominator().isOne() || r0.sign() == ExpressionNode::Sign::Negative) {
+    if (!r0.isInteger() || r0.sign() == ExpressionNode::Sign::Negative) {
       return replaceWithUndefinedInPlace();
     }
   }
   if (c1.type() == ExpressionNode::Type::Rational) {
     Rational r1 = static_cast<Rational &>(c1);
-    if (!r1.integerDenominator().isOne() || r1.sign() == ExpressionNode::Sign::Negative) {
+    if (!r1.isInteger() || r1.sign() == ExpressionNode::Sign::Negative) {
       return replaceWithUndefinedInPlace();
     }
   }
diff --git a/poincare/src/power.cpp b/poincare/src/power.cpp
index 1d33d3d3b..71a18a95d 100644
--- a/poincare/src/power.cpp
+++ b/poincare/src/power.cpp
@@ -39,7 +39,7 @@ ExpressionNode::Sign PowerNode::sign(Context * context) const {
   }
   if (childAtIndex(0)->sign(context) == Sign::Negative && childAtIndex(1)->type() == ExpressionNode::Type::Rational) {
     RationalNode * r = static_cast<RationalNode *>(childAtIndex(1));
-    if (r->denominator().isOne()) {
+    if (r->isInteger()) {
       assert(!Integer::Division(r->signedNumerator(), Integer(2)).remainder.isOverflow());
       if (Integer::Division(r->signedNumerator(), Integer(2)).remainder.isZero()) {
         return Sign::Positive;
@@ -67,7 +67,7 @@ int PowerNode::polynomialDegree(Context * context, const char * symbolName) cons
   }
   if (childAtIndex(1)->type() == ExpressionNode::Type::Rational) {
     RationalNode * r = static_cast<RationalNode *>(childAtIndex(1));
-    if (!r->denominator().isOne() || Number(r).sign() == Sign::Negative) {
+    if (!r->isInteger() || Number(r).sign() == Sign::Negative) {
       return -1;
     }
     Integer numeratorInt = r->signedNumerator();
@@ -93,7 +93,7 @@ bool PowerNode::isReal(Context * context) const {
   if (base->isReal(context) &&
       index->isReal(context) &&
       (base->sign(context) == Sign::Positive ||
-       (index->type() == ExpressionNode::Type::Rational && static_cast<RationalNode *>(index)->denominator().isOne()))) {
+       (index->type() == ExpressionNode::Type::Rational && static_cast<RationalNode *>(index)->isInteger()))) {
     return true;
   }
   return false;
@@ -105,7 +105,7 @@ bool PowerNode::childNeedsUserParentheses(const Expression & child) const {
      * ^(2/3, 4) --> (2/3)^{4}
      */
     if ((child.isNumber() && static_cast<const Number &>(child).sign() == Sign::Negative)
-       || (child.type() == Type::Rational && !static_cast<const Rational &>(child).integerDenominator().isOne())) {
+       || (child.type() == Type::Rational && !static_cast<const Rational &>(child).isInteger())) {
       return true;
     }
     // ^(2+3,4) --> (2+3)^{4}
@@ -166,7 +166,7 @@ bool PowerNode::childNeedsSystemParenthesesAtSerialization(const TreeNode * chil
   if (static_cast<const ExpressionNode *>(child)->isNumber() && Number(static_cast<const NumberNode *>(child)).sign() == Sign::Negative) {
     return true;
   }
-  if (static_cast<const ExpressionNode *>(child)->type() == Type::Rational && !static_cast<const RationalNode *>(child)->denominator().isOne()) {
+  if (static_cast<const ExpressionNode *>(child)->type() == Type::Rational && !static_cast<const RationalNode *>(child)->isInteger()) {
     return true;
   }
   Type types[] = {Type::Power, Type::Subtraction, Type::Opposite, Type::MultiplicationExplicite, Type::MultiplicationImplicite, Type::Division, Type::Addition};
@@ -271,7 +271,7 @@ int Power::getPolynomialCoefficients(Context * context, const char * symbolName,
       && childAtIndex(1).type() == ExpressionNode::Type::Rational)
   {
     Rational r = childAtIndex(1).convert<Rational>();
-    if (!r.integerDenominator().isOne() || r.sign() == ExpressionNode::Sign::Negative) {
+    if (!r.isInteger() || r.sign() == ExpressionNode::Sign::Negative) {
       return -1;
     }
     Integer num = r.unsignedIntegerNumerator();
@@ -309,7 +309,7 @@ Expression Power::shallowReduce(ExpressionNode::ReductionContext reductionContex
   ExpressionNode::Type baseType = base.type();
   ExpressionNode::Type indexType = index.type();
   if (SortedIsMatrix(base, reductionContext.context())) {
-    if (indexType != ExpressionNode::Type::Rational || !static_cast<Rational &>(index).integerDenominator().isOne()) {
+    if (indexType != ExpressionNode::Type::Rational || !static_cast<Rational &>(index).isInteger()) {
       return replaceWithUndefinedInPlace();
     }
     if (baseType != ExpressionNode::Type::Matrix) {
@@ -449,7 +449,7 @@ Expression Power::shallowReduce(ExpressionNode::ReductionContext reductionContex
       } else if (r.isMinusHalf()) {
         // (x+iy)^(-1/2)
         result = complexBase.squareRoot(reductionContext).inverse(reductionContext);
-      } else if (r.integerDenominator().isOne() && r.unsignedIntegerNumerator().isLowerThan(Integer(10))) {
+      } else if (r.isInteger() && r.unsignedIntegerNumerator().isLowerThan(Integer(10))) {
         if (r.sign() == ExpressionNode::Sign::Positive) {
           // (x+iy)^n, n integer positive n < 10
           result = complexBase.powerInteger(r.unsignedIntegerNumerator().extractedInt(), reductionContext);
@@ -627,7 +627,7 @@ Expression Power::shallowReduce(ExpressionNode::ReductionContext reductionContex
     Power powerBase = static_cast<Power &>(base);
     // Check if a > 0 or c is Integer
     if (powerBase.childAtIndex(0).sign(reductionContext.context()) == ExpressionNode::Sign::Positive // a > 0
-        || (indexType == ExpressionNode::Type::Rational && static_cast<Rational &>(index).integerDenominator().isOne())) // c integr
+        || (indexType == ExpressionNode::Type::Rational && static_cast<Rational &>(index).isInteger())) // c integr
     {
       /* If the complexFormat is real, we check that the inner power is defined
        * before applying the rule (a^b)^c -> a^(b*c). Otherwise, we return
@@ -646,7 +646,7 @@ Expression Power::shallowReduce(ExpressionNode::ReductionContext reductionContex
   if (!letPowerAtRoot && baseType == ExpressionNode::Type::MultiplicationExplicite) {
     MultiplicationExplicite multiplicationBase = static_cast<MultiplicationExplicite &>(base);
     // Case 1: (a*b*c*...)^n = a^n*b^n*c^n*... if n integer
-    if (indexType == ExpressionNode::Type::Rational && static_cast<Rational &>(index).integerDenominator().isOne()) {
+    if (indexType == ExpressionNode::Type::Rational && static_cast<Rational &>(index).isInteger()) {
       return simplifyPowerMultiplication(reductionContext);
     }
     // Case 2: (a*b*...)^r -> |a|^r*(sign(a)*b*...)^r if a not -1
@@ -695,7 +695,7 @@ Expression Power::shallowReduce(ExpressionNode::ReductionContext reductionContex
     Expression additionIndexChild0 = additionIndex.childAtIndex(0);
     if (additionIndexChild0.type() == ExpressionNode::Type::Rational) {
       const Rational rationalIndex = static_cast<Rational &>(additionIndexChild0);
-      if (rationalIndex.unsignedIntegerNumerator().isOne() && !rationalIndex.integerDenominator().isOne()) {
+      if (rationalIndex.unsignedIntegerNumerator().isOne() && !rationalIndex.isInteger()) {
         /* Do not reduce a^(1/q+c+...) to avoid potential infinite loop:
          * a^(1/q+c+...) --> a^(1/q)*a^(c+...) --> a^(1/q+c+...)*/
         /* TODO: do something more sensible here:
@@ -731,7 +731,7 @@ Expression Power::shallowReduce(ExpressionNode::ReductionContext reductionContex
   if (!letPowerAtRoot
       && indexType == ExpressionNode::Type::Rational
       && !static_cast<Rational &>(index).signedIntegerNumerator().isZero()
-      && static_cast<Rational &>(index).integerDenominator().isOne()
+      && static_cast<Rational &>(index).isInteger()
       && baseType == ExpressionNode::Type::Addition)
   {
     // Exponent n
@@ -793,7 +793,7 @@ Expression Power::shallowReduce(ExpressionNode::ReductionContext reductionContex
   /* We could use the Newton formula instead which is quicker but not immediate
    * to implement in the general case (Newton multinome). */
   // (a+b)^n with n integer -> a^n+?a^(n-1)*b+?a^(n-2)*b^2+...+b^n (Newton)
-  if (!letPowerAtRoot && childAtIndex(1)->type() == ExpressionNode::Type::Rational && static_cast<const Rational *>(childAtIndex(1))->denominator().isOne() && childAtIndex(0)->type() == ExpressionNode::Type::Addition && childAtIndex(0)->numberOfChildren() == 2) {
+  if (!letPowerAtRoot && childAtIndex(1)->type() == ExpressionNode::Type::Rational && static_cast<const Rational *>(childAtIndex(1))->isInteger() && childAtIndex(0)->type() == ExpressionNode::Type::Addition && childAtIndex(0)->numberOfChildren() == 2) {
     Rational * nr = static_cast<Rational *>(childAtIndex(1));
     Integer n = nr->numerator();
     n.setNegative(false);
@@ -920,7 +920,7 @@ Expression Power::simplifyRationalRationalPower(ExpressionNode::ReductionContext
   // this is a^b with a, b rationals
   Rational a = childAtIndex(0).convert<Rational>();
   Rational b = childAtIndex(1).convert<Rational>();
-  if (b.integerDenominator().isOne()) {
+  if (b.isInteger()) {
     Rational r = Rational::IntegerPower(a, b.signedIntegerNumerator());
     if (r.numeratorOrDenominatorIsInfinity()) {
       return Power::Builder(a, b);
diff --git a/poincare/src/prediction_interval.cpp b/poincare/src/prediction_interval.cpp
index 2acf5027b..915a468fb 100644
--- a/poincare/src/prediction_interval.cpp
+++ b/poincare/src/prediction_interval.cpp
@@ -67,7 +67,7 @@ Expression PredictionInterval::shallowReduce(ExpressionNode::ReductionContext re
   }
   if (c1.type() == ExpressionNode::Type::Rational) {
     Rational r1 = static_cast<Rational &>(c1);
-    if (!r1.integerDenominator().isOne() || r1.sign() == ExpressionNode::Sign::Negative) {
+    if (!r1.isInteger() || r1.sign() == ExpressionNode::Sign::Negative) {
       return replaceWithUndefinedInPlace();
     }
   }
@@ -76,7 +76,7 @@ Expression PredictionInterval::shallowReduce(ExpressionNode::ReductionContext re
   }
   Rational r0 = static_cast<Rational &>(c0);
   Rational r1 = static_cast<Rational &>(c1);
-  if (!r1.integerDenominator().isOne() || r1.sign() == ExpressionNode::Sign::Negative || r0.sign() == ExpressionNode::Sign::Negative || Integer::NaturalOrder(r0.unsignedIntegerNumerator(), r0.integerDenominator()) > 0) {
+  if (!r1.isInteger() || r1.sign() == ExpressionNode::Sign::Negative || r0.sign() == ExpressionNode::Sign::Negative || Integer::NaturalOrder(r0.unsignedIntegerNumerator(), r0.integerDenominator()) > 0) {
     return replaceWithUndefinedInPlace();
   }
   /* [r0-1.96*sqrt(r0*(1-r0)/r1), r0+1.96*sqrt(r0*(1-r0)/r1)]*/
diff --git a/poincare/src/rational.cpp b/poincare/src/rational.cpp
index 5785e3c4e..c4ed722a5 100644
--- a/poincare/src/rational.cpp
+++ b/poincare/src/rational.cpp
@@ -72,7 +72,7 @@ int RationalNode::serialize(char * buffer, int bufferSize, Preferences::PrintFlo
   }
   buffer[bufferSize-1] = 0;
   int numberOfChar = signedNumerator().serialize(buffer, bufferSize);
-  if (denominator().isOne()) {
+  if (isInteger()) {
     return numberOfChar;
   }
   if (numberOfChar >= bufferSize-1) {
@@ -97,7 +97,7 @@ Expression RationalNode::setSign(Sign s, ReductionContext reductionContext) {
 
 Layout RationalNode::createLayout(Preferences::PrintFloatMode floatDisplayMode, int numberOfSignificantDigits) const {
   Layout numeratorLayout = signedNumerator().createLayout();
-  if (denominator().isOne()) {
+  if (isInteger()) {
     return numeratorLayout;
   }
   Layout denominatorLayout = denominator().createLayout();
diff --git a/poincare/src/round.cpp b/poincare/src/round.cpp
index b6bc32ce6..32d5e3055 100644
--- a/poincare/src/round.cpp
+++ b/poincare/src/round.cpp
@@ -56,7 +56,7 @@ Expression Round::shallowReduce(ExpressionNode::ReductionContext reductionContex
   if (childAtIndex(0).type() == ExpressionNode::Type::Rational && childAtIndex(1).type() == ExpressionNode::Type::Rational) {
     Rational r1 = childAtIndex(0).convert<Rational>();
     Rational r2 = childAtIndex(1).convert<Rational>();
-    if (!r2.integerDenominator().isOne()) {
+    if (!r2.isInteger()) {
       return replaceWithUndefinedInPlace();
     }
     const Rational ten = Rational::Builder(10);
diff --git a/poincare/test/rational.cpp b/poincare/test/rational.cpp
index 87baebe4f..fd0a0589a 100644
--- a/poincare/test/rational.cpp
+++ b/poincare/test/rational.cpp
@@ -60,6 +60,11 @@ QUIZ_CASE(poincare_rational_properties) {
   quiz_assert(!Rational::Builder(3,2).isMinusHalf());
   quiz_assert(Rational::Builder(10).isTen());
   quiz_assert(!Rational::Builder(-1).isTen());
+  quiz_assert(Rational::Builder(-1).isInteger());
+  quiz_assert(Rational::Builder(9).isInteger());
+  quiz_assert(Rational::Builder(9,3).isInteger());
+  quiz_assert(Rational::Builder(-9,3).isInteger());
+  quiz_assert(!Rational::Builder(9,10).isInteger());
 }
 
 static inline void assert_add_to(const Rational i, const Rational j, const Rational k) {