We can simplify 12.50 to 12.5, because the zero is behind the decimal point, and has nothing after it.
We multiply 12.5 (the cost of each portion) by 12 (the amount of portions) to get the total cost. If you are allowed to use a calculator you can just plug in the numbers, as so:
12.5 x 12 = 150
If not, and you need to show work, It'll look like the image I attached.
If you're unsure, you can use division to check your answer.
