diff --git a/facho/fe/form/__init__.py b/facho/fe/form/__init__.py
index 395c748..69add30 100644
--- a/facho/fe/form/__init__.py
+++ b/facho/fe/form/__init__.py
@@ -71,6 +71,12 @@ class Amount:
                                                           rounding=decimal.ROUND_HALF_EVEN ))
             self.currency = currency
 
+    def fromNumber(self, val):
+        return Amount(val, currency=self.currency)
+    
+    def round(self, prec):
+        #return Amount(self.amount.quantize(Decimal('1.' + '0' * prec), rounding=decimal.ROUND_HALF_EVEN))
+        return Amount(round(self.amount, prec))
 
     def __round__(self, prec):
         return round(self.amount, prec)
@@ -88,17 +94,27 @@ class Amount:
             raise AmountCurrencyError()
         return round(self.amount, DECIMAL_PRECISION) == round(other.amount, DECIMAL_PRECISION)
 
-    def __add__(self, other):
+    def _cast(self, val):
+        if type(val) in [int, float]:
+            return self.fromNumber(val)
+        if isinstance(val, Amount):
+            return val
+        raise TypeError("cant cast to amount")
+    
+    def __add__(self, rother):
+        other = self._cast(rother)
         if not self.is_same_currency(other):
             raise AmountCurrencyError()
         return Amount(self.amount + other.amount, self.currency)
 
-    def __sub__(self, other):
+    def __sub__(self, rother):
+        other = self._cast(rother)
         if not self.is_same_currency(other):
             raise AmountCurrencyError()
         return Amount(self.amount - other.amount, self.currency)
 
-    def __mul__(self, other):
+    def __mul__(self, rother):
+        other = self._cast(rother)
         if not self.is_same_currency(other):
             raise AmountCurrencyError()
         return Amount(self.amount * other.amount, self.currency)
@@ -125,18 +141,16 @@ class Quantity:
         self.code = code
 
     def __mul__(self, other):
-        if isinstance(other, Amount):
-            return Amount(self.value) * other
         return self.value * other
 
     def __lt__(self, other):
-        if isinstance(other, Amount):
-            return Amount(self.value) < other
         return self.value < other
 
     def __str__(self):
         return str(self.value)
 
+    def __repr__(self):
+        return str(self)
 
 @dataclass
 class Item:
@@ -323,11 +337,15 @@ class Price:
     amount: Amount
     type_code: str
     type: str
+    quantity: int = 1
 
     def __post_init__(self):
         if self.type_code not in codelist.CodigoPrecioReferencia:
             raise ValueError("type_code [%s] not found" % (self.type_code))
+        if not isinstance(self.quantity, int):
+            raise ValueError("quantity must be int")
 
+        self.amount *= self.quantity
 
 @dataclass
 class PaymentMean:
diff --git a/facho/fe/form_xml/invoice.py b/facho/fe/form_xml/invoice.py
index 40bfe2d..279fcfb 100644
--- a/facho/fe/form_xml/invoice.py
+++ b/facho/fe/form_xml/invoice.py
@@ -540,7 +540,7 @@ class DIANInvoiceXML(fe.FeXML):
             line.set_element('./cac:Price/cbc:PriceAmount', invoice_line.price.amount, currencyID=invoice_line.price.amount.currency.code)
             #DIAN 1.7.-2020: FBB04
             line.set_element('./cac:Price/cbc:BaseQuantity',
-                             invoice_line.quantity,
+                             invoice_line.price.quantity,
                              unitCode=invoice_line.quantity.code)
 
 
diff --git a/tests/test_amount.py b/tests/test_amount.py
index 76a0d8c..fdc99fe 100644
--- a/tests/test_amount.py
+++ b/tests/test_amount.py
@@ -20,3 +20,14 @@ def test_amount_equals():
     assert price1 == price2
     assert price1 == form.Amount(100) + form.Amount(10)
     assert price1 == form.Amount(10) * form.Amount(10) + form.Amount(10)
+    assert form.Amount(110) == (form.Amount(1.10) * form.Amount(100))
+    
+def test_round():
+    # Entre 0 y 5 Mantener el dígito menos significativo
+    assert form.Amount(1.133).round(2) == form.Amount(1.13)
+    # Entre 6 y 9 Incrementar el dígito menos significativo
+    assert form.Amount(1.166).round(2) == form.Amount(1.17)
+    # 5, y el segundo dígito siguiente al dígito menos significativo es cero o par Mantener el dígito menos significativo
+    assert str(form.Amount(1.1560).round(2)) == str(form.Amount(1.15))
+    # 5, y el segundo dígito siguiente al dígito menos significativo es impar Incrementar el dígito menos significativo
+    assert form.Amount(1.1569).round(2) == form.Amount(1.157)
diff --git a/tests/test_fe_form.py b/tests/test_fe_form.py
index 2c01b96..02dc430 100644
--- a/tests/test_fe_form.py
+++ b/tests/test_fe_form.py
@@ -170,6 +170,7 @@ def test_invoice_cufe(simple_invoice_without_lines):
     assert cufe == '8bb918b19ba22a694f1da11c643b5e9de39adf60311cf179179e9b33381030bcd4c3c3f156c506ed5908f9276f5bd9b4'
 
 
+
 def test_credit_note_cude(simple_credit_note_without_lines):
     simple_invoice = simple_credit_note_without_lines
     simple_invoice.invoice_ident = '8110007871'