Order of operations is a set of rules. It tells you the order in which to compute so that you’ll getthe same answer that anyone else would get.

Compute 6 + 4 x 3 ÷ 6 =

If you work in order from leftto right, you’d do this first. 6 + 4 x 3 ÷ 6 =

10

10 x 3 ÷ 6

30

30 ÷ 6 = 5

But, if you knew about orderof operations, you’d do this.

6 + 4 x 3 ÷ 6

12

6 + 12 ÷ 6

2

6 + 2 = 8

If you work in order from leftto right, you’d do this first. 6 + 4 x 3 ÷ 6 =

10

10 x 3 ÷ 6

30

30 ÷ 6 = 5

But, if you knew about orderof operations, you’d do this.

6 + 4 x 3 ÷ 6

12

6 + 12 ÷ 6

2

6 + 2 = 8

6 + 4 x 3 ÷ 6 really does equal 8. The order of operationsmakes sure that there is only one correct answer for thisor any other computation.

Click on the computer foran Order of Operation mini lesson

Sometimes, when you write a problem, you don’t want to follow the regular order of operations.

You can use parentheses to say do this first.

Each of 5 friends got a full box of snacks and an extra 6 snacks. Write an equation to show how many snacks are in all those boxes and all thoseextra snacks. (Each snack box has the same amount of snacks.) represents a snack box

Each of 5 friends got a full box of snacks and an extra 6 snacks. Write an equation to show how many snacks are in all those boxes and all those extra snacks

Even if you don’t know how many snacks are in a box, you can write an expression to show

how many.

5 x + 6

Each of 5 friends got a full box of snacks and an extra 6 snacks. Write an equation to show how many snacks are in all those boxes and all those extra snacks

5 x + 6

The order of operations would tell you to multiply 5 by then add 6. But every friend has a sum of snacks ( + 6) and youwant to multiply the sum by 5.

The order of operations would tell you to multiply 5 by then add 6. But every friend has a sum of snacks ( + 6) and youwant to multiply the sum b y 5.

Use parentheses to group the sum: 5 x ( + 6).So, if = 4, you compute like this:

5 x (4 + 6)

105 x = 50

To make sure that everyone finds the same answer whencomputing, we have rules called order of operations.

1. Compute inside the parentheses.2. Calculate the exponents and roots.

3.Multiply or divide left to right.

4.Add or Subtract left to right.

1. Compute inside the parentheses.2. Calculate the exponents and roots.

3.Multiply or divide left to right.

4.Add or Subtract left to right.

This silly sentence mayhelp you remember:“Please excuse my dear Aunt Sally.”

5 friends have collected 300 cans. They take themto the store that pays 6¢ each for aluminum cans.Fifteen of the cans are not aluminum. If theyshare the money equally, how much does each friendget?

Set up the equation

300 cans, 15 of them worthless 300 - 15

Each aluminum can is worth 6¢ 6 x (300 – 15)

Five friends share equally 6 x (300 – 15) ÷ 5

6 x (300 – 15) ÷ 5

Follow the Order of Operations

1. Compute inside parentheses 6 x (285) ÷ 5

2. Do the exponents or roots no exponents or roots

3. Multiply or divide left to right

1710 ÷ 5 = 342

Each friend will get 342¢ or $3.42 for the cans.

6 x (285) = 1710

4 x (53 – 18) ÷ 5 =

Remember : Please excuse my dear Aunt Sally

1. Compute inside the parentheses

4 x (53 – 18) ÷ 5 =

354 x ÷ 5 =

4 x (53 – 18) ÷ 5 =

2.

Remember : Please excuse my dear Aunt Sally

Do the exponents or roots

354 x ÷ 5 =

no exponents or roots

3.Multiply or divide left to right

140 ÷ 5 = 28

16 ÷ 4 + (4 – 3) x 4

Remember : Please excuse my dear Aunt Sally

16 ÷ 4 + (4 – 3) x 4

1 16 ÷ 4 + x 4

44 +

4 + 4 = 8