M2 Lesson 13

© 2022 Great Minds PBC. This presentation is solely for use in conjunction with delivery of the Eureka Math2® curriculum in the District during the term of the

agreement for access to the Great Minds digital platform between Great Minds and the District.

Reproduction and distribution of this PowerPoint or any slides, in whole or any part, is not permitted. Additionally, this PowerPoint and the slides may not be

altered in any way. For more information, visit greatminds.org.

LESSON
13

Decimal Addition and Subtraction

Why is place value important when adding and subtracting decimals?

Our goal today:

We will

• understand how to set up addition and subtraction problems with decimals using the standard algorithm

• fluently add and subtract multi-digit decimals using the standard algorithm

• Use academic vocabulary to describe what we are doing

First we will warm up by adding and subtracting numbers in unit form

Remember--unit form is when you break a number apart by the place value, for example 56 is 5 tens and 6 ones.

Math Response

3 tens 5 ones + 4 tens 3 ones

Type answer here

Correct Answer: 78

Deg^°

Rad

Math Response

3 tenths 5 hundredths + 4 tenths 5 hundredths

Type answer here

Correct Answer: .8

Deg^°

Rad

Math Response

4 hundreds 6 tens 7 ones - 2 hundreds 3 tens 5 ones

Type answer here

Correct Answer: 232

Deg^°

Rad

Math Response

4 tens 6 ones 7 tenths + 2 tens 3 ones 5 tenths

Type answer here

Correct Answer: 70.2

Deg^°

Rad

Math Response

7 tenths 2 hundredths- 4 tenths 3 hundredths

Type answer here

Correct Answer: .29

Deg^°

Rad

Math Response

5 tens 6 ones - 2 ones 8 tenths

Type answer here

Correct Answer: 53.2

Deg^°

Rad

© 2022 Great Minds PBC. This presentation is solely for use in conjunction with delivery of the Eureka Math2® curriculum in the District during the term of the agreement for access to the Great Minds digital platform

between Great Minds and the District. Reproduction and distribution of this PowerPoint or any slides, in whole or any part, is not permitted. Additionally, this PowerPoint and the slides may not be altered in any way. For
more information, visit greatminds.org.

Multiple Choice

When adding or subtracting decimals you set up your problem by

• lining up the decimals so that the ones and tenths are in in the same place

• lining up the numbers from the right so that each number is directly under a number

• lining up the numbers from the left so that each number is directly under a number

• It doesn't matter. Do it the way you like.

Open Ended

What do you think the problem is?

Math Response

205 + 457 + 91=30.057

The sum is correct.

Please place the decimal in the correct spot in each addend so that the equation is true.

Type answer here

Correct Answer: 20.5+0.457+9.1

Deg^°

Rad

Multiple Select

If you estimate the sum for 20.5 + 45.7 + 9.1 you could get.

• 21+50+9=80

• 20+50+10=80

• 20+100+90=210

• 205+457+91=753

Math Response

20.5+45.7+9.1=753

The sum is correct, but the addends are not written properly. Please place the decimals so that the equation is true.

Type answer here

Correct Answer: 205+457+91=753

Deg^°

Rad

Multiple Choice

When you add or subtract decimals what do you need to do to set your problem up?

• line up the decimals

• put the largest number on top

• line up by the number on the left

• line up by the number on the right

© 2022 Great Minds PBC. This presentation is solely for use in conjunction with delivery of the Eureka Math2® curriculum in the District during the term of the agreement for access to the Great Minds digital platform

between Great Minds and the District. Reproduction and distribution of this PowerPoint or any slides, in whole or any part, is not permitted. Additionally, this PowerPoint and the slides may not be altered in any way. For
more information, visit greatminds.org.

Fix it please.

Multiple Choice

1.6 + 0.02=1.8 fix so that this the sum is the same, but the addends are written correctly

• 1.6 + 0.2

• 1.6 + 2.0

• 1.6 + 0.002
• 1.6 + 0.0020

Multiple Choice

1.6 + 0.02=1.8 fix so that the equation is true without changing the addends

• 1.6 + 0.02=1.62

• 1.6 + 0.2= 1.62

• 1.6 + 0.02=1.8

• 1.6 + 0.02=1.26

Draw

QUICKLY draw how you are feeling right now

© 2022 Great Minds PBC. This presentation is solely for use in conjunction with delivery of the Eureka Math2® curriculum in the District during the term of the agreement for access to the Great Minds digital platform

between Great Minds and the District. Reproduction and distribution of this PowerPoint or any slides, in whole or any part, is not permitted. Additionally, this PowerPoint and the slides may not be altered in any way. For
more information, visit greatminds.org.

You know what

to do!

Multiple Choice

1.006- 0.2=1.004

The difference is incorrect. Please fix the subtrahend (the number being subtracted) so that the equation is true.

• 1.006-0.02=1.004

• 1.006- 0.002=1.004

• 1.006- 0.2=1.004

• 1.006-0.0002=1.004

Let's look at what Ryan did

Turn and talk to the person next to you about what Ryan did. The person closest to the side of the room with the door goes first.

Open Ended

Explain what Ryan did. I am looking for mathematical reasoning, not spelling or grammar.

Now look at Tyler's work

​Talk to your partner about what Tyler did, this time starting with the person who went last

Poll

Which way seems easier to you?

• Ryan's way

• Tyler's way

• Both are the same

• I don't understand what either of them did

Math Response

page 165 #2 608.05-51.308=

Type answer here

Correct Answer: 556.742

Deg^°

Rad

Multiple Select

page 166 #4

A baseball pitcher throws a baseball. The baseball reaches home plate in about 0.458 seconds. A softball pitcher throws a softball. the softball reaches home plate in about 0.419 seconds. How many fewer seconds does it take for the softball to reach home plate than the baseball?

FIRST-which words signal the operation we need to use to answer this question?

• How many fewer

• How many

• than

• does it take

Multiple Choice

A baseball pitcher throws a baseball. The baseball reaches home plate in about 0.458 seconds. A softball pitcher throws a softball. the softball reaches home plate in about 0.419 seconds. How many fewer seconds does it take for the softball to reach home plate than the baseball?

Which operation will we use?

• addition

• subtraction

• multiplication

• division

Multiple Choice

A baseball pitcher throws a baseball. The baseball reaches home plate in about 0.458 seconds. A softball pitcher throws a softball. the softball reaches home plate in about 0.419 seconds. How many fewer seconds does it take for the softball to reach home plate than the baseball?

Which equation will we use?

• 0.458-0.419=

• 0.419-0.458=

Math Response

A baseball pitcher throws a baseball. The baseball reaches home plate in about 0.458 seconds. A softball pitcher throws a softball. the softball reaches home plate in about 0.419 seconds. How many fewer seconds does it take for the softball to reach home plate than the baseball?

Please solve

Type answer here

Correct Answer: 0.039

Deg^°

Rad

Multiple Choice

How do you read the number 0.039?

• 39 hundredths

• 39 thousandths

• 39 hundred

• 39 thousand

Math Response

page 166 #5

Write the unknown digits so that the sum is correct.

Type answer here

Correct Answer: 4.6525

Deg^°

Rad

Math Response

page 166 #6

Write the unknown digits so that the difference is correct

Type answer here

Correct Answer: 1.031

Deg^°

Rad

Math Response

page 167 #1

684.49 + 731.287=

Type answer here

Correct Answer: 1415.777

Deg^°

Rad

Math Response

page 167 #2

745.406-61.97=

Type answer here

Correct Answer: 683.436

Deg^°

Rad

Draw

Did we meet out goal to fluently add and subtract multi-digit decimals using the standard algorithm?

Draw your arrow where you think we hit on the target.

Poll

How do you feel about adding and subtracting decimals?

• I've got this!

• I'm almost there.

• I'm not sure

• I have no idea.

Open Ended

Why is place value important when adding and subtracting decimals?