Except the numbers on the bottom calculator are 1224, not 1234 like the top ones. Also, I don’t know if the light beams
on the light bulbs make a difference. There are 5 each on the top bulbs and only 4 each on the group of three. Does that mean the group of three are only worth 4/5 each of the top bulbs? So worth 12 instead of 15?
My problem with these is there are enough differences, intentional or not, that only the person who drew it originally knows the answer because only he/she knows which of the differences means anything.