ORDER OF OPERATIONS

INTRODUCTION

• Hello little friends,

• Welcome to our Mathematics programme for Grade 7.

• Today we will talk of the ORDER OF OPERATIONS, that is,

• How & Why order is important in the 4 main operations:

• Addition, Subtraction, Multiplication & Division.

• We will discover together what happens if the correct order is NOT applied.

• BODMAS will be introduced and its applications to some examples.

• Let’s start with the 4 basic operations in Mathematics.

THE FOUR BASIC OPERATIONS ARE:

Addition

Subtraction

Multiplication

Division

WHY IS IT IMPORTANT?

CALCULATE + ×

VIK + ×

= ×

=

MEG + × = + =

WHO IS RIGHT?

VIK OR MEG?

BODMAS

Brackets(Calculation inside Brackets comes first)

Orders (Numbers involving powers, squares or

square roots)

Division

Multiplication

Addition

Subtraction

LET’S TRY IT NOW!

+ ×

Multiplication first = +

Then Addition =

USE OF CALCULATORS AND EXCEL

EXAMPLE + − ×

APPLYING BODMAS + − ×

Brackets first = + ×

Next is Multiplication = +

Finally Addition =

EXAMPLE + 2 × – ÷

APPLYING BODMAS + 2 × – ÷

Orders first = + × – ÷

Both multiplication and division, proceed from left to right Next is Multiplication = + × – ÷

Then Division = + – ÷

= + –

For both addition and subtraction, Proceed from left to right = –=

HARDER EXAMPLE − × ÷ − +

APPLYING BODMAS

Brackets First − × ÷ − +

Next we do the division = − × ÷ − +

= − ÷ +

Finally we add = − +

=

ADDITIONAL EXERCISES FOR PRACTICE

a. 4 + 5 x (2+4) ÷ 3 -7

b. 44 ÷ 11 + (15 - 9) x 12

c. ÷ +

d. (15 – 2) + 7 x (21 ÷ 3)

ADDITIONAL EXERCISES FOR PRACTICE

OBSERVATIONS

Addition and Multiplication are commutative,

that is, changing the ORDER will not change the result

+ = + =

× = × =

However Subtraction and Division are NOT commutative!

Changing the ORDER will change the result − ≠ −

÷ ≠ ÷

Conclusion

• We have talked of:

•Order of Operations, to be worked out following the rule BODMAS:

• Brackets, Orders, Division, Multiplication, Addition & Multiplication and discussed a few examples.

•We’ve shown you how Addition & Subtraction are Commutative whereas Multiplication & Division is NOT commutative.

• The correct Order of operations is important for obtaining the exact answer. You are now advised to work out the Exercises for Practice.

•Good bye little friends.

LINKS FOR ADDITIONAL PRACTICE

•

• Additional Practice for Order of Operations

• http://www.softschools.com/math/order_of_operations/order_of_operations_worksheets/3-step_order_of_operations_worksheet2.html

•

• Finding the missing operation

• http://www.softschools.com/math/order_of_operations/order_of_operations_worksheets/order_of_operations_missing_operation_worksheet2.html

•

• Order of Operations – Game

• http://www.math-play.com/Order-of-Operations-Millionaire/order-of-operations-millionaire-game.html

ENJOY THE BEAUTY OF MATHEMATICS!