Given a problem like,

3×5-2, you might be wondering “how do I solve this?” since there are two possible ways.

Option 1:

(3×5)-2=15-2=13
Option 2:

3×(5-2)=3×3=9
This is where the order of operations comes in, since there is only one correct answer.

The order of operations are rules that tell us which operation to perform first when calculating an algebraic expression.

Here is the order of operations:

1. Parentheses

2. Exponents

3. Multiplication and Division (from left to right)

4. Addition and Subtraction (from left to right)

When calculating an algebraic expression, go down the order of operations, starting with parentheses, and perform the operations that apply.

There is an acronym used to remember the order of operations, PEMDAS (parentheses, exponents, multiplication, division, subtraction, and addition). The phrase “Please Excuse My Dear Aunt Sally” is also used to help remember the order by using the first letter of each word.

Looking back at the problem above and knowing the order of operations, we now can see that the answer is 13, option 1.

Let’s see some examples using the order of operations.

First example (

click
here):

8×5-(6+10)÷2
1. Calculate within parentheses

=8×5-16÷2
We simplified what was in the parentheses.

2. Multiplication and Division (from left to right)

=40-16÷2
=40-8
We multiplied and divided starting from the left of the expression, making our way to the right.

3. Addition and Subtraction (from left to right)

=40-8
=32
Next example (

click
here):

2×(5×6+2^2 )+(8÷2)
1. Calculate within parentheses – Evaluate

(5×6+2^2)
(5×6+2^2 )=(5×6+4)
=(30+4)
=34
Make sure you apply the order of operations when calculating inside the parentheses

Now we have: 2×(5×6+2^2 )+(8÷2)=2×34+(8÷2)

2. Calculate within parentheses – Evaluate

(8÷2)
8÷2=4
Now we have: 2×34+(8÷2)=2×34+4

3. Multiplication and Division (from left to right)

=2×34+4
=68+4
4. Addition and Subtraction (from left to right)

=68+4
=72
Last example (

click
here):

6+(2(4+2))^2-5^2
1. Calculate within parentheses

=6+(2(6) )^2-5^2
=6+12^2-5^2
2. Exponents

=6+144-5^2
=6+144-25
3. Addition and Subtraction (from left to right)

=150-25
=125
Learning the order of operations is essential in math because they will guide you to the correct answer. For more help or practice with the order of operations, check out Symbolab’s

Practice.

Until next time,

Leah