diff --git a/mapytex/calculus/core/MO/monomial.py b/mapytex/calculus/core/MO/monomial.py
index 26b9836..d461f45 100644
--- a/mapytex/calculus/core/MO/monomial.py
+++ b/mapytex/calculus/core/MO/monomial.py
@@ -103,6 +103,15 @@ class MOMonomial(MO):
         >>> x = MOstrPower('x', 2)
         >>> MOMonomial(4, x)
         <MOMonomial 4x^2>
+        >>> MOMonomial(4, 'x')
+        <MOMonomial 4x>
+        >>> MOMonomial(4, 'x', 1)
+        <MOMonomial 4x>
+        >>> MOMonomial(4, 'x', 2)
+        <MOMonomial 4x^2>
+        >>> x = MOstrPower('x', 2)
+        >>> MOMonomial(4, x, 3)
+        <MOMonomial 4x^6>
         >>> MOMonomial(0, x)
         Traceback (most recent call last):
             ...
@@ -118,30 +127,22 @@ class MOMonomial(MO):
             _power = MO.factory(_variable.power.value * power)
             _variable = _variable.variable
         elif isinstance(_variable, MOstr):
-            _variable = variable
             _power = MO.factory(power)
+            _variable = variable
         else:
             raise MOError(f"variable need to be a MOstrPower or a MOstr. Got {type(variable)}.")
 
         self._variable = _variable
         self._power = _power
 
-        if self._power == 1:
-            if self._coefficient == 1:
-                _tree = self._variable
+        try:
+            if self._coefficient.value != 1:
+                _tree = Tree("*", self._coefficient, self.strpower)
             else:
-                _tree = Tree("*",
-                             self._coefficient,
-                             self._variable
-                             )
-        else:
-            if self._coefficient == 1:
-                _tree = MOstrPower(self._variable, self._power)
-            else:
-                _tree = Tree("*",
-                             self._coefficient,
-                             MOstrPower(self._variable, self._power)
-                             )
+                _tree = self.strpower
+        except AttributeError:
+            _tree = Tree("*", self._coefficient, self.strpower)
+
 
         MO.__init__(self, _tree)