Adding and Subtracting Decimals

SWBAT fluently add and subtract decimals.

Warm Up1. Find the prime factorization of 32

2. What is the LCM of 12 and 18?

3. Serena wants to create snack bags for a trip she is going on. She has 6 granola bars and 10 pieces of dried fruit. If the snack bags should be identical without any food left over, what is the greatest number of snack bags Serena can make?

Where do we see Decimals? Spending Money Earning Money Balancing Savings &

Checking Accounts Accountants Sports If you have an

allowance and you start to spend it, you can subtract what you have spent to know how much you still have left

Anytime you are purchasing multiple items, you are adding decimals

If you are saving money to purchase gifts or items for yourself you need to add the costs together to know how much you need

Anytime you want to find out how much you would save by buying one item over the other you are subtracting decimals

23.1 + 5.8

18 + 1.23

54.7 + 21.2

0.63 + 10.251

Adding Decimals

Subtracting Decimals

5.6 – 3.5

19.84 – 4.26

9.27 – 3.143

58-7.53

10 – 0.5

74.84 – 73.23

Steps to Add and Subtracting:

1) Stack the decimals2) Line them up by their decimal

points3) Add zeros to any empty place

values4) Add or subtract like normal5) Bring decimal straight down in

your answer

Question 1

Marcus is 1.5 meters tall. His sister, Carol, is 0.1 meter taller than Marcus. Their father is 0.2 meters taller than Carol. How tall is Carol? How tall is their father?

Carol is 1.6 m tall. Their father is 1.8 m tall

Question 2

Jennifer brought $14.75 to the baseball game. She spent $3.45 for a hot dog and soda. How much money does she have left?

$11.30 left over

Question 3Allie rides her bike to school which is 1.2 miles

away. If she stops at her friend Jessica’s house which is .5 miles from her house. How much farther does she need to ride to get to school?

.7 miles farther

Question 4 Andrew weighs 83.42 pounds. His twin brother,

Christopher, weighs 87.12 pounds. How many more pounds does Christopher weigh?

3.7 pounds more

Question 5Kendall the tiger recently got weighed. He

weighed 306.78 pounds. His companion, Wilson, weighed 38.49 pounds more. How much did Wilson weigh in pounds?

345.27 pounds

Question 6 Daniel had saved $105.65. He gave away

$34.08 to charity and bought a new bike helmet for $29.97. How much money in dollars and cents did he have left over?

$41.60 left over

Exit Ticket1. Add: 3.4 + 5.892. Subtract: 9.04 – 7.23. Ms. Dalton went to Dunkin

Donuts and bought a donut for $0.79 and a coffee for $2.35. What was her total?