If you want to edit a value easily based on something else in the program, you can make it so the number is a variable instead. Judging by the code as well, you want there to be a new line, currently it’s not doing that since you need to use "\n"
So the code should look like:
int arrows = 4;
String myString = "Money = 10" + "\n" + "Arrows = " + arrows;
If you then change the value of the integer arrows
before declaring the string it will be different.