diff --git a/sale.py b/sale.py
index 7e119e1..2f35471 100644
--- a/sale.py
+++ b/sale.py
@@ -127,13 +127,8 @@ class Sale(metaclass=PoolMeta):
 
     @classmethod
     def get_residual_amount(cls, sales, names):
-        result = {n: {s.id: Decimal(0) for s in sales} for n in names}
-        for name in names:
-            for sale in sales:
-                if sale.invoice_state != 'none':
-                    result[name][sale.id] = sale.total_amount - sale.paid_amount
-        return result
-
+        return {n: {s.id: s.total_amount - s.paid_amount if s.state != 'cancel'
+                    else Decimal(0) for s in sales} for n in names}
 
     @classmethod
     def search_residual_amount(cls, name, clause):