"Something" is a variable. A variable is a number that we do not know. The variable will be x.
5,652 is the total; the total is 12 plus x.
5652 = 12 + x
Subtract 12 from each side
5652 - 12 = 12 + x - 12
5640 = x
change it around
x = 5640.
5640 is your answer