Well I don’t know if you can see the code but here it is:
let apple = “5”;
let apple = "5"; # this returns a string
let banana = 5; # this returns an integer
apple += 1; # this concatenates "5" and "1" as strings
banana += 1; # this adds 5 and 1 as integers
+ for string concatenation. Its used in plenty of languages, like Python and C++ for example.