6NS.3 Jadyn’s Snacks

Jaydn has $20.56. She buys an apple for 79 cents and a granola bar for $1.76.

A. How much money did Jadyn spend?

B. How much money does Jadyn have now?

3.3 Adding and Subtracting Decimals

EQ: How do you solve problems involving the addition, subtraction,

multiplication, and division of decimals? (SPI: 0606.2.3) /CC.6EE.2b

Welcome to Fifth Third Bank

Date Description of Transaction

Payment

Debit (-)

Deposit

Credit (+)

Balance

Jun 24 Opening Deposit 200.00 200.00

200.00

Jul 4 Buy Beach Towel 14.99 -14.99

50.10

Aug 3 School Supplies 28.03 -28.03

22.07

Aug 30 Homecoming Dance 6.00 -6.00

16.07

Sep 12 Progress Report Money 10.00 +10.00

26.07

Mr. Stewart’s Checkbook

Date Description of Transaction

Payment

Debit (-)

Deposit

Credit (+)

Balance

Jun 24 Opening Deposit 200.00 200.00

200.00

Jul 4 Buy Beach Towel 14.99 14.99

185.01

Aug 3 School Supplies 28.03 28.03

156.98

Aug 30 Homecoming Dance 6.00 6.00

150.98

Sep 12 Progress Report Money

10.00 10.00

160.98

Place value can help you understand and write and compare decimal numbers.

Review: Decimal Place Value

ADDING OR SUBTRACTING DECIMALS

What do you do when you are adding or subtracting decimals?

Line’em UpDrop’em Down

3.3 ADDING AND SUBTRACTING

DECIMALS

I can add and subtract decimals and use estimation to check my answers

ADDING OR SUBTRACTING

9.900 9.500 9.826+ 8.120 37.346

Line up decimals. Add zeros as place

holders. Add. Bring the decimal

down from the problem.

9.9 + 9.5 + 9.826 + 8.12 = ?

SUBTRACTING EXAMPLE: 5 – 0.64 = ?

Line up decimals. Add the decimal point to

the whole number 5. Add zeros as place

holders. Subtract. Bring the

decimal down from the problem.

5.00 - 0.64 4.36

THINK ABOUT IT….

Why is it important to line up your decimals?

Why do we add zeros?

Add.

9.70

9.30

+9.4528.45

Align the decimal points.

Use zeros as placeholders.

Add. Then place the decimal point.

Check the reasonableness of this answer using rounding. Does your answer make sense?

EXAMPLES:

1. 12 – 10.12 = ? 1.88

2. 3.8 + 0.7 = ? 4.5

3. 6 - 1.12 = ? 4.88

Essential Question

How do you solve problems involving the addition, subtraction, multiplication, and division of decimals?

Lesson Quiz

Find each sum or difference.

1. 8.3 + 2.7

2. 9.7 – 4

3. 22.6 + 8.4

4. Evaluate 12.76 – x for x = 8.41.

5. During an ice-skating competition, Dawn

received the following scores: 4.8, 5.2, 5.4.

What was Dawn’s total score?

5.7

11

31

4.35

15.4

ESTIMATION

Why is estimation a good way to check your answers?

How else could you check your answers?

PROBLEM SOLVING

Samantha is balancing her checkbook.

The balance from her last statement was $213.33. Since than she made 1 deposit of $42.05 and wrote 1 check for $28.33. How much money does Samantha have left in her account?

You go to Falcon Flight and buy popcorn for $1.35, a soda for $1.20 and a slice of pizza for $2.33. You pay with a $5.00 bill. Write an equation to show how much change you will receive and solve it. Let c = the change you get back $5.00 – (1.35 + 1.20 + 2.33) = C 1.35 + 1.20 + 2.33 + c = 5.00 C=$0.12

EXAMPLES:

4. 6.5 + 12.12 = ?18.62

5. 7 +15.876 + 0.56 = ?23.436

6. 44.587 + 7.023 + 5 = ?56.61

EXAMPLES:

7. 44.98 – 14.32 = ?30.66

8. 8 – 3.56 = ?4.44

Adding and Subtracting Decimals Showdown!!!