diff --git a/poincare/include/poincare/decimal.h b/poincare/include/poincare/decimal.h
index e92d5f4e6..1f08f6554 100644
--- a/poincare/include/poincare/decimal.h
+++ b/poincare/include/poincare/decimal.h
@@ -86,7 +86,7 @@ class Decimal final : public Number {
 friend class Number;
 friend class DecimalNode;
 public:
-  static int Exponent(const char * integralPart, int integralPartLength, const char * fractionalPart, int fractionalPartLength, const char * exponent, int exponentLength);
+  static int Exponent(const char * integralPart, int integralPartLength, const char * fractionalPart, int fractionalPartLength, const char * exponent, int exponentLength, bool exponentIsNegative = false);
   Decimal(const char * integralPart, int integralPartLength, const char * fractionalPart, int fractionalPartLength, int exponent);
   Decimal(DecimalNode * node) : Number(node) {}
   Decimal(Integer m, int e);
diff --git a/poincare/include/poincare/number.h b/poincare/include/poincare/number.h
index 3199ac149..999a703fc 100644
--- a/poincare/include/poincare/number.h
+++ b/poincare/include/poincare/number.h
@@ -27,7 +27,8 @@ class Number : public Expression {
 public:
   Number(const NumberNode * node) : Expression(node) {}
   /* Return either a Rational, a Decimal or an Infinity. */
-  static Number ParseDigits(const char * digits, size_t length);
+  static Number ParseDigits(const char * digits, size_t length); // TODO: remove me when homemade parser is ready
+  static Number ParseNumber(const char * integralPart, size_t integralLength, const char * decimalPart, size_t decimalLenght, bool exponentIsNegative, const char * exponentPart, size_t exponentLength);
   /* Return either a Decimal or an Infinity or an Undefined. */
   template <typename T> static Number DecimalNumber(T f);
   /* Return either a Float or an Infinity or an Undefined */
diff --git a/poincare/src/decimal.cpp b/poincare/src/decimal.cpp
index 896c7b922..e8ed7ef85 100644
--- a/poincare/src/decimal.cpp
+++ b/poincare/src/decimal.cpp
@@ -220,8 +220,7 @@ template<typename T> T DecimalNode::templatedApproximate() const {
   return f*std::pow((T)10.0, (T)(m_exponent-numberOfDigits+1));
 }
 
-int Decimal::Exponent(const char * integralPart, int integralPartLength, const char * fractionalPart, int fractionalPartLength, const char * exponent, int exponentLength) {
-  bool exponentNegative = false;
+int Decimal::Exponent(const char * integralPart, int integralPartLength, const char * fractionalPart, int fractionalPartLength, const char * exponent, int exponentLength, bool exponentNegative) {
   if (exponentLength > 0 && exponent[0] == '-') {
     exponent++;
     exponentNegative = true;
diff --git a/poincare/src/number.cpp b/poincare/src/number.cpp
index 5fafca02a..df38e7f93 100644
--- a/poincare/src/number.cpp
+++ b/poincare/src/number.cpp
@@ -80,6 +80,32 @@ Number Number::ParseDigits(const char * digits, size_t length) {
   return Decimal(integral, integralLength, fractional, fractionalLength, exp);
 }
 
+Number Number::ParseNumber(const char * integralPart, size_t integralLength, const char * decimalPart, size_t decimalLenght, bool exponentIsNegative, const char * exponentPart, size_t exponentLength) {
+  // Integer
+  if (exponentLength == 0 && decimalLenght == 0) {
+    Integer i(integralPart, integralLength, false);
+    if (!i.isInfinity()) {
+      return Rational(i);
+    }
+  }
+  int exp;
+  // Avoid overflowing int
+  if (exponentLength < Decimal::k_maxExponentLength) {
+    exp = Decimal::Exponent(integralPart, integralLength, decimalPart, decimalLenght, exponentPart, exponentLength, exponentIsNegative);
+  } else {
+    exp = exponentIsNegative ? -1 : 1;
+  }
+  // Avoid Decimal with exponent > k_maxExponentLength
+  if (exponentLength >= Decimal::k_maxExponentLength || exp > Decimal::k_maxExponent || exp < -Decimal::k_maxExponent) {
+    if (exp < 0) {
+      return Decimal(0.0);
+    } else {
+      return Infinity(false);
+    }
+  }
+  return Decimal(integralPart, integralLength, decimalPart, decimalLenght, exp);
+}
+
 template <typename T>
 Number Number::DecimalNumber(T f) {
   if (std::isnan(f)) {