Order of Operations 

Introduction

Math expressions use grouping symbols like brackets [], braces {} and parentheses . We now evaluate expressions involving order of operations with whole numbers using such grouping symbols.

Problem 1

Evaluate the following expression

[3 +15+6 ÷ 7] 4

Solution

Step 1:

We must follow the rule of order of operations PEMDAS.

We start with the innermost grouping, the parentheses 15+6

[3 +(15 + 6) ÷ 7] 4 =

[3 + 21 ÷ 7] 4

Step 2:

We next evaluate the remaining grouping, brackets [3 + 21 ÷ 7]

Step 3:

We perform all multiplication and division before any addition or subtraction

[3 + 21 ÷ 7]

[3 + 3]=

6

Step 4:

We then evaluate the last expression

6 4 = 24

Step 5:

So [3 +15+6 ÷ 7] 4 = 24

Problem 2

Evaluate the following expression

[37 129 3] ÷ 7

Solution

Step 1:

We follow the rule of order of operations PEMDAS.

We start with the innermost grouping, the parentheses 129

[37 (12 9) 3] ÷ 7 =

[37 3 3] ÷ 7

Step 2:

We next evaluate the remaining grouping, brackets [37 3 3]

Step 3:

We perform all multiplication and division before any addition or subtraction

[37 3 3]=

[37 9] =

28

Step 4:

We then evaluate the last expression

28 ÷ 7 = 4

Step 5:

[37 129 3] ÷ 7 = 4