diff --git a/mapytex/calculus/core/compute/__init__.py b/mapytex/calculus/core/compute/__init__.py
index 4b3d8c8..4abac57 100644
--- a/mapytex/calculus/core/compute/__init__.py
+++ b/mapytex/calculus/core/compute/__init__.py
@@ -20,11 +20,12 @@ from .power import power
 from ..MO.mo import MOnumber, MOstr
 from ..MO.fraction import MOFraction
 from ..MO.monomial import MOstrPower, MOMonomial
+from ..MO.polynomial import MOpolynomial
 
 from itertools import product
 from tabulate import tabulate
 
-MOS = [ MOnumber, MOstr, MOFraction, MOstrPower, MOMonomial ]
+MOS = [ MOnumber, MOstr, MOFraction, MOstrPower, MOMonomial, MOpolynomial]
 
 OPERATIONS = {
         "+": add,
@@ -67,7 +68,7 @@ def compute_capacities(node):
 
     :example:
     >>> compute_capacities("+")
-    [['+', 'MOnumber', 'MOstr', 'MOFraction', 'MOstrPower', 'MOMonomial'], ['MOnumber', True, False, True, False, False], ['MOstr', False, True, False, False, True], ['MOFraction', True, False, True, False, False], ['MOstrPower', False, False, False, True, True], ['MOMonomial', False, True, False, True, True]]
+    [['+', 'MOnumber', 'MOstr', 'MOFraction', 'MOstrPower', 'MOMonomial', 'MOpolynomial'], ['MOnumber', True, False, True, False, False, True], ['MOstr', False, True, False, False, True, True], ['MOFraction', True, False, True, False, False, True], ['MOstrPower', False, False, False, True, True, True], ['MOMonomial', False, True, False, True, True, True], ['MOpolynomial', True, True, True, True, True, True]]
 
     """
     op = OPERATIONS[node]
diff --git a/mapytex/calculus/core/typing/__init__.py b/mapytex/calculus/core/typing/__init__.py
index 7c56f73..32d6fb5 100644
--- a/mapytex/calculus/core/typing/__init__.py
+++ b/mapytex/calculus/core/typing/__init__.py
@@ -13,23 +13,24 @@ Computing with MO
 from .exceptions import TypingError
 from .add import add
 # from .minus import minus
-# from .multiply import multiply
+from .multiply import multiply
 from .divide import divide
 from .power import power
 
 from ..MO.mo import MOnumber, MOstr
 from ..MO.fraction import MOFraction
 from ..MO.monomial import MOstrPower, MOMonomial
+from ..MO.polynomial import MOpolynomial
 
 from itertools import product
 from tabulate import tabulate
 
-MOS = [ MOnumber, MOstr, MOFraction, MOstrPower, MOMonomial ]
+MOS = [ MOnumber, MOstr, MOFraction, MOstrPower, MOMonomial, MOpolynomial]
 
 OPERATIONS = {
         "+": add, 
         # "-": minus, 
-        # "*": multiply,
+        "*": multiply,
         "/": divide,
         "^": power,
         }
@@ -46,7 +47,10 @@ def typing(node, left_v, right_v):
         operation = OPERATIONS[node]
     except KeyError:
         raise TypingError(f"Unknown operation ({node}) in typing")
-    return operation(left_v, right_v)
+    try:
+        return operation(left_v, right_v)
+    except NotImplementedError:
+        raise TypingError(f"Can't create new MO with {node}, {type(left_v)} and {type(right_v)}")
 
 def typing_capacities(node):
     """ Test an operation through all MOs 
@@ -54,6 +58,10 @@ def typing_capacities(node):
     :param operation: string which represent an (mo, mo) -> mo
     :returns: { (motype, motype): True/False } when it's implemented
 
+    :example:
+    >>> typing_capacities("*")
+    [['*', 'MOnumber', 'MOstr', 'MOFraction', 'MOstrPower', 'MOMonomial', 'MOpolynomial'], ['MOnumber', False, True, False, True, False, False], ['MOstr', True, False, True, False, False, False], ['MOFraction', False, True, False, True, False, False], ['MOstrPower', True, False, True, False, False, False], ['MOMonomial', False, False, False, False, False, False], ['MOpolynomial', False, False, False, False, False, False]]
+
     """
     op = OPERATIONS[node]
     lines =  [[node] + [mo.__name__ for mo in MOS]]