arithmetic - order of operators [gre, gmat, sat]
TRANSCRIPT
Operator
• A mathematical task that needs to perform between two integers or
two expressions.
• Operations & Operators
• To multiple two numbers: * [ 2*3 ]
• To add two numbers: + [2+3]
• To subtract a number from other number: - [2-3]
• To divide a number with other number: / [2/3]
• To find the power of a number: ^ [2^3]
• To find the root of a number: √ [ √2 ]
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Order of Operations
• Exponents, Roots > Multiplication, Division > Addition, Subtraction
1. Firstly, look for the exponents or roots and solve it.
2. Secondly, perform the multiplication or Division operations on the result of
Step 1.
3. Thirdly, perform the addition or subtraction on the result of Step 2.
• What if you want to perform Addition operation before the
Multiplication ?
• Use Parentheses. ()
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PEMDAS
• PEMDAS is an easy way to remember the operator precedence.
• Parentheses
• Exponents/Roots
• Multiplication
• Division
• Addition
• Subtraction
• Please Excuse My Dear Aunt Sally. Easy to remember?
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PEMDAS
Examples
• Find the value of 6 + 4^2?
• Sol: 6 + 4^2
6 + 16 E
22 A
Ans : 22
• Find the value of 6 + 3 + 2^2 ?
• Sol: 6 + 3 + 2^2
6 + 3 + 4 E
Ans: 13 A
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Examples
• What if want to add 3 and 2 in the expression [ 6 + 3 + 2^2 ] first
before apply the square?
• Add the parentheses for what ever operation you to have a precedence for.
• So 6 + 3 + 2^2 becomes 6 + (3 + 2)^2
• Solve 6 + (3+2)^2
• 6 + 5^2 P
• 6 + 25 E
• 31 A
• Answer is 31.
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Examples
• Solve 7( -10/3 + 5/6 * 7)
• Sol: 7(-10/2 + 5/4 * 8) [Solve parentheses. Apply PEMDAS for
the Expression in Parentheses]
( -10/2 + 40/8 ) M
( -5 + 5 ) D
(0) A
--------------------------------------------------------------------------------------------------
7 * 0 M
0 Final Result
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Examples
• Solve 3 * 4-(6^(2-10/5)/(√25-9)* √(25-9))
Sol:
3 * 4 – (6 ^ (2-2)/(5-9)*4)
12 – (6^0/4*4)
12 – (1/4*4)
12 – 1
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Examples
• Solve 15x + 5(4x+6/2 + 3x-2)
Sol:
15x + 5 ( 4x + 3 + 3x-2)
15x + 5 (7x + 1)
15x + 35x + 5
50x + 5
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