I was once working on a job where a worker passed around the old chestnut about the 'missing dollar'. He had everyone stumped and actually believed that the error was in the math itself. Proof was this old problem, not that he was too daft to understand why it worked the way it did.
Heads were too hard to convince him that it was a trick. "No, there's error in numbers ", he said. Can you believe that?.
In case, you don't what riddle I mean, here it is:
"Three business executives eat lunch in a restaurant. They estimate that the bill should come to $30. They split the bill 3
ways and pay 10 dollars each. When the actual bill comes, it is $25. Since this is not divisible by three, they each take a
dollar back and leave the extra two dollars tip for the waiter. Since each paid nine dollars and nine times three is 27, plus
two for the waiter is 29. Where did the other dollar go? "
Trying to explain this was an effort on futility. "NO!, there's error in numbers". It had me aggravated that anyone could be that thick-headed.
With due respect of ThePerfectHacker's disdain of all Mathematical methods used in Science, this is essentially a units problem. You can't add two numbers with different units. The problem is adding the amount paid and the amount left, two different units.