Topic: Variables and Expressions C2.2 – The Order of Operations

Ontario Curriculum Expectation:

6.C2.2 evaluate algebraic expressions that involve whole numbers and decimal tenths.

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When we evaluate an expression, we need to follow the order of operations.

     1.      Brackets

     2.      Multiplication or Division

     3.      Addition or Subtraction

Evaluate  9(x − y) − 4 when  x = 6  and  y = 4.

Put the values of x and y into the expression:

     9(x − y) − 4

=  9(6 − 3) − 4

=  9(3) − 4

=  27 − 4

=  23

When there is no sign between a bracket and another value, it means multiplication will be used with two values. But remember to find the value inside the bracket first.

    9(6 − 3) means 9 × (6 − 3)

=  9 × (6 − 3)

=  9 × 3

=  27

    (10 − 9) (6 − 3) means (10 − 9) × (6 − 3)

=  (10 − 9) × (6 − 3)

=  1 × 3

=  3