The 'M' and 'D' are interchangeable as one completes the multiplication and division in the order that they appear from left to right.
The fourth and final step is to solve for the addition and subtraction in the order that they appear from left to right.
That’s what our teachers told us: Deal with whatever is in parentheses first. Finally come addition and subtraction, which are also of equal priority, with ambiguities broken again by working from left to right.
To help students in the United States remember this order of operations, teachers drill the acronym PEMDAS into them: parentheses, exponents, multiplication, division, addition, subtraction.
No wonder so many students come to see math as an inhuman, meaningless collection of arbitrary rules and procedures.
Clearly, if this latest bout of confusion on the internet is any indication, many students are failing to absorb the deeper, essential lesson.
It has to do with something that high school teachers call “the order of operations.” The latest blowup concerned this seemingly simple question: Many respondents were certain the answer was 16.
Others heard Yanny, not Laurel, and insisted the right answer was 1. “Some of y’all failed math and it shows,” said one.
The last time this came up on Twitter, I reacted with indignation: It seemed ridiculous that we spend so much time in our high-school curriculum on such sophistry.
But now, having been enlightened by some of my computer-oriented friends on Twitter, I’ve come to appreciate that conventions are important, and lives can depend on them. If everyone else is driving on the right side of the road (as in the U. The same goes if everyone else is driving on the left, as in the United Kingdom.