TypeError: list indices must be integers, not str

Question

i try something that looks like this(the actual code is too long)

number = 100
list = []

#get 25 out of the number and append it to the list
while number > 25:
number = number - 25
list.append(25)

#if there are still numbers append that number to the list
if number > 0:
list.append(number)

#loop trough all the items in the list
for x in range(len(list)):
do thing with numbers n the list