diff --git a/mapytex/calculus/API/tokens/polynomial.py b/mapytex/calculus/API/tokens/polynomial.py
index a1dfc11..45edb1b 100644
--- a/mapytex/calculus/API/tokens/polynomial.py
+++ b/mapytex/calculus/API/tokens/polynomial.py
@@ -93,7 +93,7 @@ class Polynomial(Token):
         17
         """
         return Expression(self._mo.tree)(value)
-    
+   
     def differentiate(self):
         """ Differentiate a polynome
 
@@ -111,6 +111,7 @@ class Polynomial(Token):
         2 + 6x
         """
         return Expression(self._mo.differentiate()).simplify()
+
     @property
     def roots(self):
         """ Get roots of the Polynomial """
@@ -231,15 +232,24 @@ class Quadratic(Polynomial):
 
     @property
     def a(self):
-        return self[2]
+        try:
+            return self[2]
+        except KeyError:
+            return 0
 
     @property
     def b(self):
-        return self[1]
+        try:
+            return self[1]
+        except KeyError:
+            return 0
 
     @property
     def c(self):
-        return self[0]
+        try:
+            return self[0]
+        except KeyError:
+            return 0
 
     @property
     def delta(self):
@@ -247,12 +257,33 @@ class Quadratic(Polynomial):
 
     @property
     def roots(self):
+        """ Roots of the polynom
+
+        :example:
+        >>> from ...core.MO.polynomial import MOpolynomial
+        >>> P = Quadratic(MOpolynomial('x', [1, 0, 1]))
+        >>> P.roots
+        []
+        >>> P = Quadratic(MOpolynomial('x', [4, -4, 1]))
+        >>> P.roots
+        [2.0]
+        >>> P = Quadratic(MOpolynomial('x', [1, 0, -1]))
+        >>> P.roots
+        [-1.0, 1.0]
+        """
         if self.delta._mo < 0:
             return []
         elif self.delta._mo == 0:
-            return [Expression.from_str(f"-{self.b}/(2*{self.a})").simplify()]
+            #return [Expression.from_str(f"-{self.b}/(2*{self.a})").simplify()]
+            return [round(eval(f"-{self.b}/(2*{self.a})"), 2)]
         else:
-            raise NotImplementedError("Todo!")
+            from math import sqrt
+            roots = [
+                round(eval(f"(-{self.b}-sqrt({self.delta}))/(2*{self.a})"), 2),
+                round(eval(f"(-{self.b}+sqrt({self.delta}))/(2*{self.a})"), 2),
+            ]
+            roots.sort()
+            return roots
 
 # -----------------------------
 # Reglages pour 'vim'
diff --git a/mapytex/calculus/API/tokens/token.py b/mapytex/calculus/API/tokens/token.py
index 435cbbe..924ac5b 100644
--- a/mapytex/calculus/API/tokens/token.py
+++ b/mapytex/calculus/API/tokens/token.py
@@ -80,10 +80,7 @@ class Token(object):
         return self._mo.__tex__
 
     def _operate(self, other, operation):
-        """ Make a operation between 2 Tokens, 
-        a Token and en Expression ora
-        a Token an a builtin type
-        """
+        """ Make a operation between 2 Tokens """
         from ..expression import Expression
         from ...core import Tree
         from . import factory
@@ -182,6 +179,30 @@ class Token(object):
         """
         return self._operate(other, "/")
 
+    def _get_soul(self, other=None):
+        """ Get the builtin soul of self or other """
+        if isinstance(other, Token):
+            return other._mo._value
+        elif not other is None:
+            return other
+        return self._mo._value
+
+    def __eq__(self, other):
+        return self._get_soul() == self._get_soul(other)
+
+    def __gt__(self, other):
+        return self._get_soul() > self._get_soul(other)
+
+    def __lt__(self, other):
+        return self._get_soul() < self._get_soul(other)
+
+    def __ge__(self, other):
+        return self._get_soul() >= self._get_soul(other)
+
+    def __le__(self, other):
+        return self._get_soul() <= self._get_soul(other)
+
+
 
 # -----------------------------
 # Reglages pour 'vim'