the first thing you gotta do is find the least amount of the smaller number that you can take away until it becomes a multiple of the largest number.
1356-12(1)
1344-12(2)
1332-12(3)
1320 12 factored into 1356 3 times before we reached a multiple of 15 so we subtract 3 from the total number of pizza sold and we have 93 large pizzas and 3 medium pizzas
disclaimer: as I am a human I might be wrong have a nice day
