Subtracting Decimals

Adding and Subtracting Decimals

Objective: I can determine sums and differences by adding and subtracting decimals in order to fluently add and subtract multi-digit decimals using the standard algorithm.

Multiple Choice

Julie and Doug are building a tree house out of wood boards. Julie has a board that is 1.15 meters long and Doug has board that is 0.7 meter long. What is the combined length of their boards?

Two students solved the problem. Who is correct?

Adding Decimals

Adding decimals is like adding whole numbers. Before you add, line up the decimal points. This will make sure you are adding the correct place values together.

Subtracting Decimals

Do the same thing when you subtract decimals. You may need to regroup.

Multiple Choice

Ronald paid $3.00 for a sandwich. She paid $0.85 for an apple. What is the total amount Ronald paid for lunch?

• $2.15

• $4.00

• $3.85

Open Ended

What is an important rule to remember when adding or subtracting decimals?

Numbers without a decimal point

If a number does not have a decimal point, add the decimal point at the end of the number.

Multiple Choice

How do you write the number 824 as a decimal?

• 8.24

• 0.824

• 82.4

• 824.0

Ready to try it?

Watch the two examples your teacher presents, and then you will get to practice and test your skills.

Multiple Choice

Patricia had $5.00. She spent $3.65 on a new toy. How much money does she have left?

• $1.35

• $35.65

• $8.65

Multiple Choice

Ronny paid $3.00 for a sandwich. She paid $0.85 for an apple. What is the total amount Ronny paid for lunch?

• $2.15

• $4.00

• $3.85

Multiple Choice

Snack Bar Menu:

Water Bottle: $1.00

Soda: $1.50

Candy Bar: $.75

Popcorn: $1.00

Hot Dog: $2.00

How much does it cost to buy a soda and a bag of popcorn?

• $.50

• $250

• $2.50

• $2.25

Multiple Choice

Snack Bar Menu:

Water Bottle: $1.00

Soda: $1.50

Candy Bar: $.75

Popcorn: $1.00

Hot Dog: $2.00

Marco has $5, check off all of the food/drink combinations that he can buy.

• 1 hot dog and 2 bottles of water

• 3 candy bars and 1 water bottle

• 2 hot dogs and 1 soda

• 2 bags of popcorn and a soda