# Order of Operations 11/12

from mathisfun.com:

### Operations

* "Operations"* mean things like add, subtract, multiply, divide, squaring, etc. If it isn't a number it is probably an operation.

But, when you see something like ...

7 + (6 × 52 + 3)

... what part should you calculate first?

Start at the left and go to the right?

Or go from right to left?

*Warning: Calculate them in the wrong order, and you can get a wrong answer !*

So, long ago people agreed to follow rules when doing calculations, and they are:

## Order of Operations

Do things in Parentheses First

4 × (5 + 3)=4 × 8=

**32**

4 × (5 + 3)=20 + 3=

23

(wrong)

Exponents (Powers, Roots) before Multiply, Divide, Add or Subtract

5 × 22=5 × 4=

**20**

5 × 22=102=

100

(wrong)

Multiply or Divide before you Add or Subtract

2 + 5 × 3=2 + 15=

**17**

2 + 5 × 3=7 × 3=

21

(wrong)

Otherwise just go left to right

30 ÷ 5 × 3=6 × 3=

**18**

30 ÷ 5 × 3=30 ÷ 15=

2

(wrong)

## How Do I Remember It All ... ? PEMDAS !

**P**

**P**arentheses first

**E**

**E**xponents (ie Powers and Square Roots, etc.)

**MD**

**M**ultiplication and **D**ivision (left-to-right)

**AS**

**A**ddition and **S**ubtraction (left-to-right)

Divide and Multiply rank equally (and go left to right).

Add and Subtract rank equally (and go left to right)