diff --git a/mapytex/calculus/core/MO/polynomial.py b/mapytex/calculus/core/MO/polynomial.py
index 602e7f7..2f1b414 100644
--- a/mapytex/calculus/core/MO/polynomial.py
+++ b/mapytex/calculus/core/MO/polynomial.py
@@ -73,6 +73,10 @@ class MOpolynomial(MO):
     def degree(self):
         return self._power
 
+    @property
+    def coefficients(self):
+        return self._coefs
+
 
 # -----------------------------
 # Reglages pour 'vim'
diff --git a/mapytex/calculus/core/compute/add.py b/mapytex/calculus/core/compute/add.py
index 16bf09e..35695b4 100644
--- a/mapytex/calculus/core/compute/add.py
+++ b/mapytex/calculus/core/compute/add.py
@@ -16,6 +16,7 @@ from ..tree import Tree
 from ..MO.mo import MO, MOnumber, MOstr
 from ..MO.fraction import MOFraction
 from ..MO.monomial import MOstrPower, MOMonomial
+from ..MO.polynomial import MOpolynomial
 from .exceptions import AddError
 from .arithmetic import lcm
 from .filters import special_case
@@ -236,6 +237,72 @@ def mostrpower_mostrpower(left, right):
         raise NotImplementedError("Can't add 2 MOstrPower with not same power")
     return MOMonomial(2, left.variable, left.power)
 
+@add.register((MOnumber, MOFraction), MOpolynomial)
+@special_case(add_filter)
+def monumber_mofraction(left, right):
+    """ Add a scalar to a polynomial
+
+    :example:
+    >>> a = MOnumber(1)
+    >>> b = MOpolynomial("x", [2, 3, 4])
+    >>> print(add(a, b))
+    +
+     > +
+     | > *
+     | | > 4
+     | | > ^
+     | | | > x
+     | | | > 2
+     | > *
+     | | > 3
+     | | > x
+     > +
+     | > 1
+     | > 2
+    """
+    if 0 not in right.coefficients.keys():
+        raise NotImplementedError("Polynomial with no constant, no calculus to do")
+
+    right_const = right.coefficients[0]
+    right_other = {k:v for k,v in right.coefficients.items() if k != 0}
+    right_remain = MOpolynomial(right.variable, right_other)
+
+    add_consts = Tree("+", left, right_const)
+    return Tree('+', right_remain, add_consts)
+
+@add.register(MOpolynomial, (MOnumber, MOFraction))
+@special_case(add_filter)
+def monumber_mofraction(left, right):
+    """ Add a scalar to a polynomial
+
+    :example:
+    >>> a = MOpolynomial("x", [2, 3, 4])
+    >>> b = MOnumber(1)
+    >>> print(add(a, b))
+    +
+     > +
+     | > *
+     | | > 4
+     | | > ^
+     | | | > x
+     | | | > 2
+     | > *
+     | | > 3
+     | | > x
+     > +
+     | > 1
+     | > 2
+    """
+    if 0 not in left.coefficients.keys():
+        raise NotImplementedError("Polynomial with no constant, no calculus to do")
+
+    left_const = left.coefficients[0]
+    left_other = {k:v for k,v in left.coefficients.items() if k != 0}
+    left_remain = MOpolynomial(left.variable, left_other)
+
+    add_consts = Tree("+", right, left_const)
+    return Tree('+', left_remain, add_consts)
+
 # -----------------------------
 # Reglages pour 'vim'
 # vim:set autoindent expandtab tabstop=4 shiftwidth=4:
diff --git a/mapytex/calculus/core/typing/add.py b/mapytex/calculus/core/typing/add.py
new file mode 100644
index 0000000..d9d672a
--- /dev/null
+++ b/mapytex/calculus/core/typing/add.py
@@ -0,0 +1,153 @@
+#! /usr/bin/env python
+# -*- coding: utf-8 -*-
+# vim:fenc=utf-8
+#
+# Copyright © 2017 lafrite <lafrite@Poivre>
+#
+# Distributed under terms of the MIT license.
+
+"""
+Add MO with typing
+"""
+
+from multipledispatch import Dispatcher
+from ..tree import Tree
+from ..MO.mo import MO, MOnumber, MOstr
+from ..MO.monomial import MOstrPower, MOMonomial
+from ..MO.polynomial import MOpolynomial
+from ..MO.fraction import MOFraction
+
+add_doc = """ Add MOs
+
+:param left: left MO
+:param right: right MO
+:returns: Tree or MO
+
+"""
+
+add = Dispatcher("add", doc=add_doc)
+
+@add.register((MOnumber, MOFraction), MOstr)
+def moscalar_mostr(left, right):
+    """ add a scalar with a letter to create a MOpolynomial
+
+    >>> a = MOnumber(2)
+    >>> b = MOstr('x')
+    >>> add(a, b)
+    <MOpolynomial x + 2>
+    >>> a = MOFraction(1, 5)
+    >>> add(a, b)
+    <MOpolynomial x + 1 / 5>
+    """
+    return MOpolynomial(right, [left, 1])
+
+@add.register(MOstr, (MOnumber, MOFraction))
+def moscalar_mostr(left, right):
+    """ add a scalar with a letter to create a MOpolynomial
+
+    >>> a = MOstr('x')
+    >>> b = MOnumber(2)
+    >>> add(a, b)
+    <MOpolynomial x + 2>
+    >>> b = MOFraction(1, 5)
+    >>> add(a, b)
+    <MOpolynomial x + 1 / 5>
+    """
+    return MOpolynomial(left, [right, 1])
+
+@add.register((MOnumber, MOFraction), MOstrPower)
+def moscalar_mostr(left, right):
+    """ add a scalar with a letter to create a MOpolynomial
+
+    >>> a = MOnumber(2)
+    >>> b = MOstrPower('x', 3)
+    >>> add(a, b)
+    <MOpolynomial x^3 + 2>
+    >>> a = MOFraction(1, 5)
+    >>> add(a, b)
+    <MOpolynomial x^3 + 1 / 5>
+    """
+    return MOpolynomial(right.variable, {0: left, right.power: 1})
+
+@add.register(MOstrPower, (MOnumber, MOFraction))
+def moscalar_mostr(left, right):
+    """ add a scalar with a letter to create a MOpolynomial
+
+    >>> a = MOstrPower('x', 3)
+    >>> b = MOnumber(2)
+    >>> add(a, b)
+    <MOpolynomial x^3 + 2>
+    >>> b = MOFraction(1, 5)
+    >>> add(a, b)
+    <MOpolynomial x^3 + 1 / 5>
+    """
+    return MOpolynomial(left.variable, {0: right, left.power: 1})
+
+@add.register((MOnumber, MOFraction), MOMonomial)
+def moscalar_mostr(left, right):
+    """ add a scalar with a MOMonomial to create a MOpolynomial
+
+    >>> a = MOnumber(2)
+    >>> b = MOMonomial(3, 'x', 4)
+    >>> add(a, b)
+    <MOpolynomial 3x^4 + 2>
+    >>> a = MOFraction(1, 5)
+    >>> add(a, b)
+    <MOpolynomial 3x^4 + 1 / 5>
+    """
+    return MOpolynomial(right.variable, 
+                        {0: left, right.power: right.coefficient}
+                        )
+
+@add.register(MOMonomial, (MOnumber, MOFraction))
+def moscalar_mostr(left, right):
+    """ add a scalar with a letter to create a MOpolynomial
+
+    >>> a = MOMonomial(3, 'x', 4)
+    >>> b = MOnumber(2)
+    >>> add(a, b)
+    <MOpolynomial 3x^4 + 2>
+    >>> b = MOFraction(1, 5)
+    >>> add(a, b)
+    <MOpolynomial 3x^4 + 1 / 5>
+
+    """
+    return MOpolynomial(left.variable,
+                        {0: right, left.power: left.coeffient}
+                        )
+
+@add.register(MOstr, MOstrPower)
+def moscalar_mostr(left, right):
+    """ add a scalar with a letter to create a MOpolynomial
+
+    >>> a = MOstr('x')
+    >>> b = MOstrPower('x', 3)
+    >>> add(a, b)
+    <MOpolynomial x^3 + x>
+    >>> b = MOstrPower('x', 2)
+    >>> add(a, b)
+    <MOpolynomial x^2 + x>
+    """
+    if left != right.variable:
+        raise 
+    return MOpolynomial(left , {1: 1, right.power: 1})
+
+@add.register(MOstrPower, MOstr)
+def moscalar_mostr(left, right):
+    """ add a scalar with a letter to create a MOpolynomial
+
+    >>> a = MOstrPower('x', 3)
+    >>> b = MOstr('x')
+    >>> add(a, b)
+    <MOpolynomial x^3 + x>
+    >>> a = MOstrPower('x', 2)
+    >>> add(a, b)
+    <MOpolynomial x^2 + x>
+    """
+    if right != left.variable:
+        raise 
+    return MOpolynomial(right , {1: 1, left.power: 1})
+# -----------------------------
+# Reglages pour 'vim'
+# vim:set autoindent expandtab tabstop=4 shiftwidth=4:
+# cursor: 16 del