Let's fill in the blanks for the scenario you've described:
We don't know how much money is in his bank account, so that's going to be represented as a variable. Let's use the variable x. Use an x tile to represent the money Romeo started with.
Since we're adding 5 dollars, we'll add 5 positive integer tiles.
If we add 5 dollars to his existing account, we have the expression x + 5.