If you enter each number on a calculator enter and the X or + exactly as it is written, including the minus sign in front of the penultimate "4", you will get 320 as the answer
If you were to treat it as (4X4) + (4X4) + (4-4) X 4, you get a whole 'nother answer which would be incorrect for the problem as presented.
For those of you who watch what you eat, here's the final word on nutrition and health. It's a relief to know the truth after all those conflicting nutritional studies.
1. The Japanese eat very little fat and suffer fewer heart attacks than Americans.
2. The Mexicans eat a lot of fat and suffer fewer heart attacks than Americans.
3. The Chinese drink very little red wine and suffer fewer heart attacks than Americans.
4. The Italians drink a lot of red wine and suffer fewer heart attacks than Americans.
5. The Germans drink a lot of beers and eat lots of sausages and fats and suffer fewer heart attacks than Americans.
CONCLUSION
Eat and drink what you like.
Speaking English is apparently what kills you.
>>you find it more prductive to devote all your mental energy to calculating their bill.<<
I like that one. I told one client one time when I made a BIG mistake in figuring his tax bill that I wouldn't charge him any extra for the medical exam, that his heart was in good shape.
That was the most valuable lesson I learned in graduate school. There are, of course, basics but it is often better to know where to find the exact information needed than recalling approximate information that may be outdated.