diff --git a/accounting/api/Currency.py b/accounting/api/Currency.py
new file mode 100644
index 0000000..2f75a97
--- /dev/null
+++ b/accounting/api/Currency.py
@@ -0,0 +1,52 @@
+#task 4 
+class Balance:
+
+    def __init__(self, balances):
+       
+        balanceIQD = 0
+        balanceUSD = 0
+        for i in balances:
+            if i['currency'] == 'USD':
+                balanceUSD = i['sum']
+            if i['currency'] == 'IQD':
+                balanceIQD = i['sum']
+
+       
+        self.balanceUSD = balanceUSD
+        self.balanceIQD = balanceIQD
+
+    def __add__(self, other):
+        
+        self.balanceIQD += other.balanceIQD
+        self.balanceUSD += other.balanceUSD
+        result=[{
+            'currency': 'USD',
+            'sum': self.balanceUSD
+        }, {
+            'currency': 'IQD',
+            'sum': self.balanceIQD
+        }]
+        def __zero__(self,other):
+            IQD=True
+            USD=True
+            if  self.balanceIQD ==0 and self.balanceUSD == 0:
+                IQD=False
+                USD=False
+            return{'IQD':IQD,'USD':USD}
+        def __grater__():
+            IQD=False
+            USD=False
+            if self.balanceIQD>other.balanceIQD :
+                IQD=True
+            if self.balanceUSD>other.balanceUSD:
+                USD=True
+            return{'IQD':IQD,'USD':USD}
+        def __smaller__():
+            IQD=False
+            USD=False
+            if self.balanceIQD<other.balanceIQD :
+                IQD=True
+            if self.balanceUSD<other.balanceUSD:
+                USD=True
+            return{'IQD':IQD,'USD':USD}
+            
\ No newline at end of file
diff --git a/accounting/api/account.py b/accounting/api/account.py
index e843e61..ce3ac0d 100644
--- a/accounting/api/account.py
+++ b/accounting/api/account.py
@@ -5,7 +5,7 @@
 from accounting.schemas import AccountOut, FourOFourOut, GeneralLedgerOut
 from typing import List
 from django.db.models import Sum, Avg
-from rest_framework import status
+from http import HTTPStatus
 
 from restauth.authorization import AuthBearer
 
@@ -14,7 +14,7 @@
 
 @account_router.get("/get_all", response=List[AccountOut])
 def get_all(request):
-    return status.HTTP_200_OK, Account.objects.order_by('full_code')
+    return HTTPStatus.OK, Account.objects.order_by('full_code')
 
 
 @account_router.get('/get_one/{account_id}/', response={
@@ -34,54 +34,42 @@ def get_account_types(request):
     return {t[0]: t[1] for t in AccountTypeChoices.choices}
 
 
-@account_router.get('/account-balance/{account_id}', response=GeneralLedgerOut)
-def get_account_balance(request, account_id: int):
-    account = get_object_or_404(Account, id=account_id)
-
-    balance = account.balance()
-
-    journal_entries = account.journal_entries.all()
-
-    return 200, {'account': account.name, 'balance': list(balance), 'jes': list(journal_entries)}
-
-
-@account_router.get('/account-balances/', response=List[GeneralLedgerOut])
-def get_account_balances(request):
-    accounts = Account.objects.all()
-    result = []
-    for a in accounts:
-        result.append({
-            'account': a.name, 'balance': list(a.balance())
-        })
 
-    return status.HTTP_200_OK, result
 
-
-
-
-class Balance:
-    def __init__(self, balances):
-        balance1 = balances[0]
-        balance2 = balances[1]
-
-        if balance1['currency'] == 'USD':
-            balanceUSD = balance1['sum']
-            balanceIQD = balance2['sum']
+@account_router.get('/account-balance/{account_id}', response=GeneralLedgerOut)
+def get_account_balance(request, account_id: int):
+    account = Account.objects.get(id=account_id)
+    children_accounts = account.children.all()
+    account_balance = account.balance()
+    children_balances=[]
+    balances=[]
+
+    for a in children_accounts:
+        balance = a.balance()
+        children_balances.append(list(balance))
+
+    for a in children_balances:
+        for i in a:
+            balances.append(i)
+
+    for a in list(account_balance):
+        balances.append(a)
+
+    if account.parent == None:
+        final_balance= get_balance(balances)
+    else:
+        final_balance=list(children_balances)+list(account_balance)
+
+    return HTTPStatus.OK, {'account': account.name, 'balance':final_balance}
+
+def get_balance(balances):
+    IQD_B=0
+    USD_B=0
+    for i in balances:
+        if i['currency'] == 'IQD':
+            IQD_B += i['sum'] 
         else:
-            balanceIQD = balance1['sum']
-            balanceUSD = balance2['sum']
-
-        self.balanceUSD = balanceUSD
-        self.balanceIQD = balanceIQD
-
-    def __add__(self, other):
-        self.balanceIQD += other.balanceIQD
-        self.balanceUSD += other.balanceUSD
-        return [{
-            'currency': 'USD',
-            'sum': self.balanceUSD
-        }, {
-            'currency': 'IQD',
-            'sum': self.balanceIQD
-        }]
+            USD_B += i['sum']
 
+    final_balance = [{'currency':'USD', 'sum':USD_B},{'currency':'IQD', 'sum':IQD_B}]
+    return final_balance
\ No newline at end of file
diff --git a/accounting/api/transaction.py b/accounting/api/transaction.py
index 4c5efbe..06e50af 100644
--- a/accounting/api/transaction.py
+++ b/accounting/api/transaction.py
@@ -1,5 +1,5 @@
 from ninja import Router
-from rest_framework import status
+from http import HTTPStatus
 from accounting import services
 from accounting.exceptions import AtomicAccountTransferException, ZeroAmountError, AccountingEquationError
 from accounting.schemas import TransactionIn, TransactionOut, TransactionOutSchema
@@ -16,7 +16,7 @@
 @transaction_router.post('/add-transaction', response=TransactionOutSchema)
 def add_transaction(request, transaction_in: TransactionIn):
     t = services.account_transfer(transaction_in)
-    return status.HTTP_200_OK, {
+    return HTTPStatus.OK, {
         'transaction': t,
         # 'jes': t.journal_entries.all()
     }
diff --git a/accounting/migrations/0007_alter_account_parent.py b/accounting/migrations/0007_alter_account_parent.py
new file mode 100644
index 0000000..be32e88
--- /dev/null
+++ b/accounting/migrations/0007_alter_account_parent.py
@@ -0,0 +1,19 @@
+# Generated by Django 4.0.6 on 2022-08-01 15:03
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('accounting', '0006_alter_account_code_alter_account_full_code_and_more'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='account',
+            name='parent',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='children', to='accounting.account'),
+        ),
+    ]
diff --git a/accounting/models.py b/accounting/models.py
index a7d49b7..f6359e7 100644
--- a/accounting/models.py
+++ b/accounting/models.py
@@ -49,7 +49,7 @@ class CurrencyChoices(models.TextChoices):
 
 
 class Account(models.Model):
-    parent = models.ForeignKey('self', null=True, blank=True, on_delete=models.SET_NULL)
+    parent = models.ForeignKey('self', null=True, blank=True, on_delete=models.SET_NULL,related_name='children')
     type = models.CharField(max_length=255, choices=AccountTypeChoices.choices)
     name = models.CharField(max_length=255)
     code = models.CharField(max_length=20, null=True, blank=True)
diff --git a/db.sqlite3 b/db.sqlite3
index 3cb73d5..d36304b 100644
Binary files a/db.sqlite3 and b/db.sqlite3 differ