diff --git a/challenges/01-calc.py b/challenges/01-calc.py
index 87f5190..91dbdef 100644
--- a/challenges/01-calc.py
+++ b/challenges/01-calc.py
@@ -2,3 +2,72 @@
 # input() always returns a string value. If you ever want someone
 # to enter a number you have to use the `int()` function to convert
 # what they typed in to a string.
+# user_input = input("Please enter a number: ")
+# if user_input.isdigit():
+#     number = int(user_input)
+# else:
+#     print("That was not a valid number.")
+#     exit()
+# result = number + 5
+# print("The result is:", result)
+
+# value= input('the user will see this is the terminal')
+is_running = True
+
+while is_running:
+    # display math choices and ask user to choose one
+    prompt = ">"
+    print("Hello, user 👋")
+    print("Tell me what kind of math you would like to do")
+    print("Possible choices: add, sub, mul, div")
+    math_choice = input(prompt)
+    # print(f"math choice: {math_choice}")
+
+    # ask user to input two numbers, one by
+    print("Excellent math choice! Enter the first number")
+    number_one = input(prompt)
+    print("Now, enter a second number")
+    number_two = input(prompt)
+
+    # print(number_one, number_two)
+    try:
+    # convert input to integers
+        number_one = int(number_one)
+        number_two = int(number_two)
+
+    # if/elif/else
+    # og dictionary switch
+        # switch = {
+        #     "add": number_one + number_two,
+        #     "sub": number_one - number_two,
+        #     "mul": number_one * number_two,
+        #     "div": number_one / number_two
+        # }
+
+        # if math_choice in switch:
+        #     print(f"result: {switch[math_choice]}")
+        # else:
+        #     # default for switch case
+        #     print(f"I lied, {math_choice} isn't a math choice I know about!")
+
+        # match case (new python switch)
+        match math_choice:
+            case "add":
+                print(f"{number_one} + {number_two} = {number_one + number_two}")
+            case "sub":
+                print(f"{number_one} - {number_two} = {number_one - number_two}")
+            case "mul":
+                print(f"{number_one} * {number_two} = {number_one * number_two}")
+            case "div":
+                print(f"{number_one} / {number_two} = {number_one / number_two}")
+            case _:
+                print(f"{math_choice} makes no sense to me!")
+    except ValueError as e :
+        # handle error instead of crashing
+        print("That wasn't a real number 😿")
+    
+    # ask user if they would like to exit
+    print("would you like to countinue doing math with me [y/n]?")
+    should_quit = input(prompt)
+    if should_quit == "n":
+        is_running = False
diff --git a/challenges/02-reverse.py b/challenges/02-reverse.py
index 8cf2677..9e017fb 100644
--- a/challenges/02-reverse.py
+++ b/challenges/02-reverse.py
@@ -6,3 +6,15 @@
 # several ways to reverse a string, and it's a good read!
 #
 # http://www.techbeamers.com/essential-python-tips-tricks-programmers/?utm_source=mybridge&utm_medium=blog&utm_campaign=read_more#tip1
+string = "banana"
+reversed_string = string[::-1]
+print (reversed_string)
+
+string="cucumber"
+print("".join(reversed(string)))
+
+string= "hello world"
+reversed_string = ""
+for char in string:
+    reversed_string = char + reversed_string
+print(reversed_string)
\ No newline at end of file
diff --git a/challenges/03-bank.py b/challenges/03-bank.py
index 554cb1d..4d95a80 100644
--- a/challenges/03-bank.py
+++ b/challenges/03-bank.py
@@ -1,3 +1,45 @@
 print("Welcome to Chase bank.")
 print("Have a nice day!")
+balance = 4000
+def welcome(name):
+    print("Welcome to Chase bank.")
+def withdraw():
+    pass
+def deposit():
+    amount = (input("How much would you like to deposit?"))
+    global balance
+    balance += amount
 
+def check_balance(balance):
+    print('Your current balance is', balance)
+
+
+def withdraw():
+    amount = float(input("How much would you like to withdraw?\n"))
+    global balance
+    if amount <= balance:
+        balance -= amount
+    else:
+        print("You are broke")
+
+print ("Your current balance is")
+print(balance)
+
+while True:
+    action = input("What would you like to do? (deposit, withdraw, check_balance)\n")
+
+    if action == "deposit":
+        deposit()
+        check_balance()
+    elif action == "withdraw":
+        withdraw()
+        check_balance()
+    elif action == "check_balance":
+        check_balance()
+    else:
+        print("Invalid action.")
+
+    done = input("Are you done?\n")
+    if done == "yes":
+        print("Thank you!")
+        print("Have a nice day!")
diff --git a/challenges/04-alphabetical.py b/challenges/04-alphabetical.py
index 5051ec4..db1e440 100644
--- a/challenges/04-alphabetical.py
+++ b/challenges/04-alphabetical.py
@@ -1,3 +1,21 @@
 # You'll need to use a couple of built in functions to alphabetize a string. 
 # Try to avoid looking up the exact answer and look at built in functions for
 # lists and strings instead.
+
+# convert to list approach
+# string = "supercalifragilisticexpialidocious"
+# string_list = list(string)
+# string_list.sort()
+# string = "".join(string_list)
+# print(string)
+
+
+# # sorted function approach
+# print("".join(sorted(string)))
+
+# python slice syntax (works on lists or strings)
+my_list = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
+# [slice start (default 0): slice end (default end of list): step (default 1)]
+my_list_copy = my_list[::] # make a copy with defaults
+print(my_list[::-1])
+print("hello"[::-1])