Thursday, September 6, 2012

Please Excuse My Dear Aunt Sally

I have always thought that the "PEMDAS" rule was a tad confusing.  Because, technically it should be written like this to make sense. 

P
E
MD
AS 

P: Parenthesis first
E: Exponents next
MD: Multiplication and Division next
AS: Addition and Subtraction last

The acronym PEMDAS can be deceptive, because students think they should do their multiplication before division and addition before subtraction, but that is not the case.  Notice that the M and D are grouped together, as are the A and S. This is because Multiplication and Division are at the same priority level, and should be done in left to right order. Likewise, Addition and Subtraction are at the same priority level, and should be done in left to right order. This is a great video to illustrate using the ORDER OF OPERATIONS.

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