import time

def add(numbers):
a = 0
for num in numbers:
a += num
return a

add_numbers = []

def subtract(numbers):
    b = 0
    for num in numbers:
        b -= num
    return b
sub_numbers = []

def multiply(numbers):
    c = 0
    for num in numbers:
        c *= num
    return c
mul_numbers = []

def divide(numbers):
    d = 0
    for num in numbers:
        d /= num
    return d
div_numbers = []

print("What do you want do?")
print("1.Add")
print("2.Subtract")
print("3.Multiply")
print("4.Divide")
time.sleep(1)
print("...")
print("An addition expression is something like 3+5+7 (no spaces)")
print("...")
time.sleep(1)
print("A subtraction expression is something like 3-5-7 (no spaces)")
print("...")
time.sleep(1)
print("A multiplication expression is something like 3*5*7 (no spaces)")
print("...")
time.sleep(1)
print("A division expression is something like 3/5/7 (no spaces)")
print("...")
time.sleep(1)

choice = input("Enter choice(1/2/3/4):")
time.sleep(2)
print("Checking if %s is a valid choice..." % (choice))
print("...")


while 1:
    my_string = input("Type in numbers: ")
    my_string = my_string.split()
    add_numbers = []
    for item in my_string:
        add_numbers.append(int(item)) # Convert to int and append to add_numbers.
    result = add(add_numbers) # add it all up and assign to result.
    print ("=" (result))
    if add(add_numbers) >= 1000:
        break

while 2:
    my_string = input("Type in numbers: ")
    my_string = my_string.split()
    sub_numbers = []
    for item in my_string:
        sub_numbers.append(int(item)) # Convert to int and append to sub_numbers.
    result = subtract(sub_numbers) # add it all up and assign to result.
    print ("=" (result))
    if subtract(sub_numbers) >= 100:
        break

while 3:
    my_string = input("Type in numbers: ")
    my_string = my_string.split()
    mul_numbers = []
    for item in my_string:
        mul_numbers.append(int(item)) # Convert to int and append to my_numbers.
    result = multiply(mul_numbers) # add it all up and assign to result.
    print ("=" (result))
    if multiply(mul_numbers) >= 10000:
        break

while 4:
    my_string = input("Type in numbers: ")
    my_string = my_string.split()
    div_numbers = []
    for item in my_string:
        div_numbers.append(int(item)) # Convert to int and append to my_numbers.
    result = divide(div_numbers) # add it all up and assign to result.
    print ("=" (result))
    if divide(div_numbers) >= 100:
        break

There is a problem in the indention of function add_number() at the beginning of your code.

Apart from that, don't only post ValueError, instead, post the whole error message sent by python in your console. This error message contains most of the time the precise position in your code where the error occurs.

This article has been dead for over six months. Start a new discussion instead.