| StylinRed | 04-13-2011 02:49 AM |
Quote:
Originally Posted by skiiipi
(Post 7388194)
| there's no difference... pemdas bedmas etc etc etc its just a mnemonic
here Quote:
Mnemonics are often used to help students remember the rules, but the rules taught by the use of acronyms can be misleading. In Canada the acronym BEDMAS is common. It stands for Brackets, Exponents, Division, Multiplication, Addition, Subtraction. In other English speaking countries, Brackets may be called Parentheses, or symbols of inclusion and Exponentiation may be called either Indices, Powers or Orders, and since multiplication and division are of equal precedence, M and D are often interchanged, leading to such acronyms as BIMDAS, BODMAS, BOMDAS, BERDMAS, PERDMAS, PEMDAS, and BPODMAS.
These mnemonics may be misleading, especially if the user is not aware that multiplication and division are of equal precedence, as are addition and subtraction. Using any of the above rules in the order "addition first, subtraction afterward" would also give the wrong answer.
10 - 3 + 2 \,
The correct answer is 9, which is best understood by thinking of the problem as the sum of positive ten, negative three, and positive two.
10 + (-3) + 2 \,
There is a new mnemonic featured in Danica McKellar's books Math Doesn't Suck[2] and Kiss My Math[3] that does address this very issue: "Pandas Eat: Mustard on Dumplings, and Apples with Spice." The intention being that Mustard and Dumplings is a "dinner course" and that Apples and Spice is a "dessert course." Then it becomes not a linear string of operations to do one after the other, but rather the "dinner course" operations are considered together and performed left to right, and then addition and subtraction are considered together, again performed again left to right.
| http://en.wikipedia.org/wiki/Order_of_operations http://www.mathgoodies.com/lessons/v...perations.html http://www.mathgoodies.com/lessons/v...exponents.html Quote:
How Do I Remember It All ... ? PEMDAS !
P
Parentheses first
E
Exponents (ie Powers and Square Roots, etc.)
MD
Multiplication and Division (left-to-right)
AS
Addition and Subtraction (left-to-right)
Divide and Multiply rank equally (and go left to right).
Add and Subtract rank equally (and go left to right)
After you have done "P" and "E", just go from left to right doing any "M" or "D" as you find them.
Then go from left to right doing any "A" or "S" as you find them.
Note: in the UK they say BODMAS (Brackets,Orders,Divide,Multiply,Add,Subtract), and in Canada they say BEDMAS (Brackets,Exponents,Divide,Multiply,Add,Subtract). It all means the same thing! It doesn't really matter how you remember it, just so long as you get it right.
| http://www.mathsisfun.com/operation-order-pemdas.html |
