PEMDAS - also known as "Please Excuse My Dear Aunt Sally" - is commonly used as an acronym to teach the concept of order of operations. Unfortunately, this acronym can unintentionally lead to a major misunderstanding of the concept of order of operations. Students look at PEMDAS and assume that it is the "EXACT" order in which the operations should be handled. First parentheses, then exponents, then multiplication, then division, then addition, and finally subtraction. In truth, though, the order should be first parentheses, then exponents, then multiplication OR division, whichever comes first when working from left to right in an equation. And finally addition OR subtraction, again working from left to right in the equation. A simple example of how you can get in trouble using just PEMDAS is the following equation. 50 - 10/2 + 6 x 3 Using PEMDAS, a student would first multiply 6 x 3 to get 18. Then divide 10 by 2 to get 5. Then add 5 and 18 to... read more