Monday, 1 October 2018

N9 Numbers : Order of Operations


ORDER OF OPERATIONS

For Primary School Mathematics, the following operators are usually used:

FIRST Order      :  (  )           Bracket                                        B
SECOND Order :  x   ÷        Multiplication and Division       MD
THIRD Order     :  +   -         Addition and Subtraction          AS

Tip to Remember: BMDASBaby Monsters Dance And Sing

When there are different operators [ + - x ¸ () ], then we need to follow the ORDER of OPERATION:
Do the question by:  (1) completing all FIRST order,
                                 (2) follow by all SECOND order,
                                 (3) and then the THIRD order.

Why do we need order of operations?

- To have a consistent answer to the question.

Example
            1+ 2 x 4 – 3 = 9 if we work from left to right - wrong
            1 + 2 x 4 – 3 = 3 if we work from right to left - wrong

            1+2 x 4 – 3 = 6 we use the order of operations - correct


METHOD for Order of Operation

Step 1: Look for the operators to do first
Step 2: Underline the operators
Step 3: Do calculation
Step 4: Repeat step 1-3 until question is solved.

Example:
  What is the value of
              9 + 3 x   4 – (3 + 12 ÷ 4) ÷ 2

Step1: Bracket, yes? <Do bracket first>
            order within bracket -> do ÷ first, then +

Step2: Underline
                  9 + 3   x   4 – (3+ 12÷4) ÷ 2
                                                   ↓
Step3: Do calculation                 
                     =    9 + 3 x 4 – (3 + 3)   ÷ 2
                                             ↓
Step4:          = 9 + 3 x 4  –   6 ÷ 2         < Completed bracket?, repeat step 1-3>
                                             ↓               <  Do x and ÷ >
                     =   9 +12       3          < Completed x and ÷? >
                                                        < Do + and - >
                     =  21 – 3 
                     = 18         <Complete question>

                ~~~ END ~~~ :)