Matt H. answered • 09/10/14
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PATIENT :-) Elem/Middle MATH and WRITING; HS SAT and COLLEGE ESSAYS!
Hi Angela--
"order of operations" means that when you see a big long number sentence with all sorts of multiplying, dividing, adding and subtracting, there is a specific order that you have to do the different parts in.
The basic form of this is M.D.A.S., which means first you do Multiplication and Division, THEN you can do the adding and subtracting. SO for example, if you see this:
6 + 3 x 4 - 9
you have to take care of the multiplication first, so multiply 3 x 4 before anything else. The answer to that is 12, so now let's put the 12 where the "3 x 4" used to be:
6 + 12 - 9. Since adding and subtracting go together in the order of operations, you can now finish this equation by going left to right, just like reading:
6 + 12 - 9 = 9 (Because 6 + 12 is 18, and 18 - 9 is 9.)
You can remember MDAS as "My Dear Aunt Sally," and if you are dealing with Parentheses or Exponents, they go at the beginning: PEMDAS, "please excuse my dear aunt sally."
So if we did another one:
5 x (6-2) + 7, we would do the stuff in Parentheses even before the multiplication. 6-2 is 4, so now we sub in that 4 where 6-2 was:
5 x 4 + 7 = 20 + 7 = 27
I hope this helps--order of ops is pretty easy, and it's REALLY important, so as soon as your teacher hands you a quiz, write MDAS or PEMDAS across the top so you remember to use it!
Good luck Angela!
Matt
