Order of Operations Lesson: Four Basic Operations + - × ÷

Fill in the missing numbers:

If there is Addition and Subtraction in an expression, work from left to right.
For Multiplication and Division, you also work from left to right.

If you are not familiar with these "Left to Right" rules click the
Addition and Subtraction or Multiplication and Division links.

What about problems that contain a mixture of +, -, × or ÷?
You might guess that you work from left to right, but that's NOT the case.
A new rule applies:

Multiplication and Division BEFORE
Addition and Subtraction Rule:

When there is a mix of the four basic operations, do all multiplication and division FIRST, from left to right, then do addition and subtraction, from left to right.

Apply this Order of Operations rule to a couple of examples to see how it works.

7 + 9 × 2 = ?

Following the "Multiplication and Division Before
Addition and Subtraction
" rule, first multiply 9 and 2:

7 + 9 × 2 = 7 + ______

THEN add 7 to that product: 7 + 18 = _____


Work through one more:

23 - 5 × 4 - 4 ÷ 2 = ?

Remember, × and ÷ before + and -. So start with 5 × 4:

= 23 - ______ - 4 ÷ 2

Then do the next × or ÷, 4 ÷ 2:

= 23 - 20 - ______

Now only addition and subtraction remain, so work from left to right:

= 23 - 20 - 2 = ______

Click
for a printable worksheet of problems to practice applying the "Multiplication and Division before Addition and Subtraction" rule.

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