NYS Math Module 1 Lesson 9

Objective: Add decimals using place value strategies and relate those strategies to a

written method.

5.NBT.4 Round to different place values5.NBT.1 Decompose the unit5.NBT.7 Adding decimals

Sprint

****8 minutes****Ready, Set

GO!!

Decomposing the Unit!

Say this number: 6.35

How many tenths are in 6.35? 63 tenths

6.358 = 63 tenths ____ thousandths

Think about money. How many dimes are there?

58

One more!

Say this number: 7.354

How many tenths are in 7.354?73 tenths

7.354 = 73 tenths ____ thousandths54

Rounding!

Say this number: 2.475

On your board, round to the nearest tenth.

2.5

Round 2.457 to the nearest hundredth.

2.46

Round 2.987 to the nearest hundredth.

2.99

Round 2.987 to the nearest tenth.

3

Oral Fluency

I’m going to show you a decimal, you need to say the decimal that is one

tenth more.

0.5 0.7 0.9

Now, we are going to count by hundredths. Say the decimal that is one hundredth more than the given

value.

0.05 0.07 0.09

Say the decimal that is two tenths more than the given value.

0.3 0.7What is 1 tenth more than 35

hundredths?

0.45Write down 35

hundredths, then add 1 tenth

0.11

What is 1 thousandth more than 35 hundredths?

0.351What is 1 hundredth more than 485

thousandths?

0.495Remember to

write the number first.

Word ProblemTen baseballs weigh 1,417.4 grams. About how

much does 1 baseball weigh? Round your answer to the nearest tenth of a gram. Round your answer to the nearest gram. If someone asked you, “About how much does a baseball

weigh?” which answer would you give them and why?

Share your answer with your partner.

Word Problem Solution

Adding DecimalsLet’s add 2 tenths plus 6 tenths using our place value charts.

8 tenthsWrite the addition sentence on your board.

2 tenths + 6 tenths = 8 tenthsHow is this problem the same as a whole

number addition problem?

Turn to your partner and share.

Work with your partner to solve the next two problems on your place value chart.

2 ones 3 thousandths + 6 ones 1 thousandth

2 tenths 3 thousandths + 6 hundredths

2.003 + 6.001 = 8.004

Let’s write it vertically!

0.2030.0600.263

+

1.8 + 13 tenths

Let’s look at the following problem:

How would you write 13 tenths? Write it on your white board. 13 tenths = 1.3

Solve: 1.8 + 13 tenths

3.1

Draw a picture to represent 13 tenths. You may use your place value chart.

Share with your partner

Another way to add and subtract decimals.

Tip #1 - ALWAYS line up the decimal! This means the decimals are one on top of another.

0.74 + 0.59

Let’s write it vertically!

0.740.591.33

+

Tip #2 – Add ZEROS in all the empty spaces.

Let’s give it a try.

7.048 + 5.196

Try solving the last two problems.

12.244

7.44 + 0.774

8.214

Clip art from Colleen Alaniz- Totally Terrific in Texas http://www.teacherspayteachers.com/Store/Colleen-Alaniz

Thank you for downloading this presentation.

.

Laura Stricklandwww.MyCuteGraphics.com

Backgrounds, clip art, and font by:.

The following pages are from NYS Math Modules. I minimized the images to reduce the paper waste and thought they may be

helpful to others as well. For the entire module visit:

http://www.engageny.org/resource/grade-5-mathematics-module-

2

Exit Ticket Exit Ticket

Exit Ticket Exit Ticket