diff --git a/1.py b/1.py
new file mode 100644
index 0000000..86c5c0e
--- /dev/null
+++ b/1.py
@@ -0,0 +1,10 @@
+# Question 1
+import string
+
+def letters_4_line(n):
+   with open("letters4line.txt", "w") as f:
+       alphabet1 = string.ascii_uppercase # choosing upper case
+       alphabet2 = string.ascii_lowercase  # choosing lower case
+       letters_ubb_low = [alphabet1[i:i + n]+ alphabet2[i:i + n] + "\n" for i in range(0, len(alphabet1), n)]
+       f.writelines(letters_ubb_low)
+letters_4_line(1)
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diff --git a/2.py b/2.py
new file mode 100644
index 0000000..d3cbf98
--- /dev/null
+++ b/2.py
@@ -0,0 +1,6 @@
+# Question 2
+import string
+import os
+os.chdir('C:\\Users\\Computer\\PycharmProjects\hello\\4 week') # the direction
+for alphabet in string.ascii_uppercase :
+    f = open(alphabet + ".txt", "w")
diff --git a/3.py b/3.py
new file mode 100644
index 0000000..2d3fd0d
--- /dev/null
+++ b/3.py
@@ -0,0 +1,16 @@
+# Question 3
+# LCM question:
+try:
+    numbers = list(map(int,input('enter four numbers for calculating LCM: ').strip().split())) #Enter the numbers here with spaces between them
+    numbers.sort(reverse = True)
+    numbers
+    from math import gcd      # importing the 'gcd' function from the 'math' module of math to calculate the greatest common divisor
+    lcm = 1
+    for n in numbers:
+     lcm = lcm*n//gcd(lcm, n)  # Calculating the least common multiple (L.C.M.) of the numbers
+     gcd()
+    print("The least common multiple (L.C.M.) of your four numbers is: ", lcm)
+except:
+    print("Invalid input Error: Pleass enter integer numbers.")         # warnning the user for Nan or non numerical inputs
+finally:
+    print("It is done.")
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diff --git a/4.py b/4.py
new file mode 100644
index 0000000..f82287b
--- /dev/null
+++ b/4.py
@@ -0,0 +1,40 @@
+###  Mis Calculator
+from ceil_add import *
+from ceil_div import *
+from ceil_mult import *
+from ceil_sub import *
+
+def operation():
+    while True:
+        user_choice = input (" Enter Your choice as follows: for Summation please write = (sum), for Subtraction= (sub), for Multiplication = (mul), for Division= (div):> ").lower()
+        try:        # Using try/except block to verify input entries and warn the user for incorrect inputs.
+            number_1 = float(input("Enter your first number: "))  # two parameters are float numbers  
+            number_2 = float(input("Enter your second number: "))
+        except ValueError:
+            print("Invalid Input Error: Please enter a number!")
+            continue
+# Check the user's choice and call the appropriate function from the imported module
+        if user_choice == "sum":
+            result = addition(number_1, number_2)
+            print("Summation of the two numbers is: ", result)
+        elif user_choice == "sub":
+            result = subtruction(number_1, number_2)
+            print("Subtruction of the two numbers is: ", result)
+        elif user_choice == "mul":
+            result = multiplication(number_1, number_2)
+            print("Multiplication of the two numbers is: ", result)
+        elif user_choice == "div":
+            result = division(number_1, number_2)
+            print("Division of the two numbers is: ", result)
+        #  except:
+        #     number_2 ==0 
+        #     break
+        #     print("ZeroDivisionError because number_2 should not be zero!!! ")
+        else:                      # warnning the user for incorrect inputs.
+            print("You entered something wrong! Invalid choice.")
+            continue
+        calc_again = input("If you want to use the Mis Calculator again, please type upper letter of the first word Yes or No (Y/N): ").upper()         # Ask the user if he/ she wants to use the calculater again
+        if calc_again == 'N':
+            break
+if __name__ == "__pycache__":
+    operation()
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diff --git a/ceil_add.py b/ceil_add.py
new file mode 100644
index 0000000..6d453f0
--- /dev/null
+++ b/ceil_add.py
@@ -0,0 +1,5 @@
+#  Addition
+from math import ceil
+def addition(number_1, number_2):
+    sum = number_1 + number_2
+    return ceil(sum)
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diff --git a/ceil_div.py b/ceil_div.py
new file mode 100644
index 0000000..03c6c3a
--- /dev/null
+++ b/ceil_div.py
@@ -0,0 +1,9 @@
+#  Division
+from math import ceil
+def division(number_1, number_2):
+    try:
+       div = number_1 / number_2
+    except ZeroDivisionError as e:
+       return e
+    else:
+     return ceil(div)
\ No newline at end of file
diff --git a/ceil_mult.py b/ceil_mult.py
new file mode 100644
index 0000000..86c0d74
--- /dev/null
+++ b/ceil_mult.py
@@ -0,0 +1,5 @@
+#  Multiplication
+from math import ceil
+def multiplication(number_1, number_2):
+    mul = number_1 * number_2
+    return ceil(mul)
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diff --git a/ceil_sub.py b/ceil_sub.py
new file mode 100644
index 0000000..d243dc3
--- /dev/null
+++ b/ceil_sub.py
@@ -0,0 +1,5 @@
+#  Subtruction
+from math import ceil
+def subtruction(number_1, number_2):
+    sub = number_1 - number_2
+    return ceil(sub)
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