Answer: Hello, in this case you have some options for the equation y - 12.
1) 12 subtracted from a number y.
Where you are subtracting 12 units of the number y.
2) the number y decreased by 12.
where you are decreasing the total units of y by 12.
3) the difference between a number y and 12.
This is the most general phrase, where you are calculating the difference in the number units of y and 12.
