GRE Math : How to find order of operations
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Example Questions
Example Question #1 : How To Find Order Of Operations
Evaluate:
3 + 2(1 * 9 + 8) – 9/3
82
37/3
34
36
76/3
34
Order of operations
Do everything inside the parenthesis first:
3 + 2(17) – 9/3
next, do multiplication/division
3 + 34 – 3
= 34
Example Question #212 : Arithmetic
3 + 4 * 5 / 10 – 2 =
3
1.5
7
5
5.5
3
Here we must use order of operations. First we multiply 4 * 5 = 20. Then 20 / 10 = 2. Now we can do the addition and substraction. 3 + 2 – 2 = 3. If you started at the beginning on the left hand side and not used order of operations, you would mistakenly choose 1.5 as the correct answer.
Example Question #2 : How To Find Order Of Operations
Order of operations can be remembered by PEMDAS (Please Excuse My Dear Aunt Sally): Parentheses Exponents Multiplication Division Addition Subtraction.
[7(5 + 2) – (5 * 8)]2 =
1: Inner parentheses = [ 7(7) – 40 ]2
2: Outer brackets = [ 49 – 40 ]2 = 92
3: Exponents = 81
Example Question #3 : How To Find Order Of Operations
This looks daunting as one long equation, but let's look at each piece and then add them all together.
2–3 = 1/23 = 1/8
250 = 1
(–218)1 = –218
6251/4 = 5
(–27)1/3 = –3
Then, 2–3 + 250 + (–218)1 + 7/8 – 6251/4 + (–27)1/3 = 1/8 + 1 – 218 + 7/8 – 5 – 3 = –224.
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