That line from the second paragraph of the article has been well-supported by the comments.

It would be nice if we had an unambiguous order of precedence for operations. Instead, we don't even have an unambiguous list of operations if we can't agree on whether 2(1+2) in the original equation is the same as 2 x (1+2).

I was taught explicitly in school that implicit multiplication was evaluated before explicit multiplication and division. Meaning the answer to the original question is definitely 1, and so 9 is the wrong answer - in my high school math classes. For my kids' math classes, the 'correct' answer would have varied depending on which kid's classes you were looking at.

My only quibble with the author's statement is to note that the question may indeed be well-defined IF you have explicitly defined ahead of time what rules of precedence you're using. Otherwise, it's like asking whether a 17-year-old can legally buy an alcoholic beverage without knowing what country you're in.

That line from the second paragraph of the article has been well-supported by the comments.

It would be nice if we had an unambiguous order of precedence for operations. Instead, we don't even have an unambiguous list of operations if we can't agree on whether 2(1+2)

in the original equationis the same as 2 x (1+2).I was taught

explicitlyin school that implicit multiplication was evaluated before explicit multiplication and division. Meaning the answer to the original question is definitely 1, and so 9 is the wrong answer -in. For my kids' math classes, the 'correct' answer would have varied depending on which kid's classes you were looking at.myhigh school math classesMy only quibble with the author's statement is to note that the question may indeed be well-defined IF you have explicitly defined ahead of time what rules of precedence you're using. Otherwise, it's like asking whether a 17-year-old can legally buy an alcoholic beverage without knowing what country you're in.