Surprisingly it works. Though the result is a bit strange at first. As if Python put one string after the other.
Indeed the + operator is defined when we have two strings on the two sides. It is then called concatenation.
In general you'll have to learn what the matematical operators do when they are applied to values other than numbers. Usually the operation they do is quite logical. You just need to find the right logic.
a = "19" b = "23" c = a + b print(c) # 1923 d = b + a print(d) # 2319