diff --git a/problem2.py b/problem2.py
new file mode 100644
index 0000000..8fc7b96
--- /dev/null
+++ b/problem2.py
@@ -0,0 +1,6 @@
+import pandas as pd
+
+def big_countries(world: pd.DataFrame) -> pd.DataFrame:
+    df=world[(world['area']>=3000000) |  (world['population']>=25000000)][['name','population','area']]
+    print (df)
+    return df
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diff --git a/problem3.py b/problem3.py
new file mode 100644
index 0000000..9bf14f2
--- /dev/null
+++ b/problem3.py
@@ -0,0 +1,6 @@
+import pandas as pd
+
+def find_products(products: pd.DataFrame) -> pd.DataFrame:
+    df=products[(products['low_fats']=='Y') & (products['recyclable']=='Y')][['product_id']]
+    # df=df[['product_id']]
+    return df
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diff --git a/problem4.py b/problem4.py
new file mode 100644
index 0000000..9d5a10e
--- /dev/null
+++ b/problem4.py
@@ -0,0 +1,10 @@
+import pandas as pd
+
+def find_customers(customers: pd.DataFrame, orders: pd.DataFrame) -> pd.DataFrame:
+    df=customers[~customers['id'].isin(orders['customerId'])]
+    return df[['name']].rename(columns={'name':'Customers'})
+    
+def find_customers(customers: pd.DataFrame, orders: pd.DataFrame) -> pd.DataFrame:
+    df=customers.merge(orders,left_on='id',right_on='customerId',how='left')
+    df=df[df['customerId'].isna()][['name']].rename(columns={'name':'Customers'})
+    return df
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