How to interact with characters if they are in a text notepad?

Question

Python

I want to interact with numbers that are written in a standard text editor - notepad.
Let's say I want to multiply a number by 200 by 2, then it turns out not 400 as usual, but 200200. How can I fix it so that I can work with numbers normally?
here is the code:

file = open(file="testtext.txt") #в файле написано число 200
file1 = file.read()
print(file1)
print(file1*2)

Answer 1

Lord, why doesn't anyone even read an elementary book?
You are working with a string data type, but it is necessary with an integer.
Bring one type to another and you will be happy.
Until the next problem