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*Chapter 3: Adding and Subtracting Decimals · 3.8 Adding Decimals & 3.9 Subtracting Decimals Use...*

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Chapter 3: Adding and

Subtracting DecimalsMAFS.5.NBT.1.1,MAFS.5.NBT.1.3 ,

MAFS.5.NBT.1.4 , MAFS.5.NBT.2.7

Ch 3 Vocabulary Words

1. Benchmark - A familiar number used as a point of reference Example:

2. Place value - The value of each digit in a number based on the location of the digit

3. Tenth- One of ten equal parts Example: 0.7 = seven tenths or 7/10

4. Hundredth- One of 100 equal parts Examples: 0.56, ___ 56/100 , fifty-six hundredths

5. Round- To replace a number with one that is simpler and is approximately the same size as the original number Example: 114.6

rounded to the nearest ten is 110 and to the nearest one is 115.

6. Sequence- an ordered list of numbers

7. Term- a number in a sequence

8. Thousandth- One of one thousand equal parts Example: 0.006 = six thousandths or 6/1,000

3.1 Thousandths

Thousandths are smaller parts than hundredths. If one hundredth is divided into

ten equal parts, each part is one thousandth.

3.1 Continued

1. 0.6 is 10 times as much as __

1. 0.008 is 1/10 of __

https://www.youtube.com/watch?v=UEi3crjbCaE

Decimal Ten times as much as 1/10 of

0.03 0.3 0.003

0.7

0.01

https://www.youtube.com/watch?v=UEi3crjbCaE

3.2 Place Value of Decimals

You can use a place-value chart to understand decimals. Whole numbers are to

the left of the decimal point. Decimals are to the right.

Standard Form: 1.726

Word Form: one and seven hundred twenty-six thousandths

Expanded Form: (1x1) + (7 x 1/10) + (2 x 1/100) + (6 x 1/1000)

Tens Ones Decimal

Point

Tenths Hundredths Thousandths

Standard 1 7 2 6

Expanded 1x1 7 x 1/10 2x1/100 6x1/1000

Decimals 1.0 0.7 0.02 0.006

3.2 Continued

Decimal Value of underlined digit

Word Form Expanded Form

0.287 0.2 or two tenths two hundred eighty-seven

thousandths

(2 x 1/10) + (8 x 1/100) +

(7 x 1/1000)

6.359

2.704

Engage NY Module 1 Lesson 5

3.3 Compare and Order Decimals

How can you use place value to compare and order decimals?

3.3 On Your Own

Compare. Write , or =.

1. 8.673 8.637 2. 1.036 1.306

Name the greatest place-value position where the digits differ. Name the greater number.

3. 3.579; 3.564 4. 9.572; 9.637

Order from least to greatest.

5. 2.007; 2.714; 2.09; 2.97 6. 1.703; 1.037; 1.37; 1.073

Round to the underlined digit.

7. 0.428 8. 3.19

3.5 Decimal Addition & 3.6 Decimal Subtraction (using models) Videos: https://www.youtube.com/watch?v=Mxo9EVFVGMU &

https://www.youtube.com/watch?v=0sjLdohzEVo

Addition with models

1) 1.37 + 1.85 =

Subtraction with Models

2) 2.82 - 1.47 =

https://www.youtube.com/watch?v=Mxo9EVFVGMUhttps://www.youtube.com/watch?v=0sjLdohzEVo

Drawing Models

1. 0.9 - 0.2 =

2. 0.5 +0.12 =

3.8 Adding Decimals & 3.9 Subtracting Decimals

Use place value to add and subtract decimals. Make sure to line the decimals up

first and then solve your problem.

Estimate. Then find the sum or difference.

1. 5.83 Estimate: ____ 2. 12.3 Estimate: ____

- 2.18 + 4.9

3. Find the sum. seven and twenty-five hundredths added to nine and four tenths

4. Find the difference. three and seventy-two hundredths subtracted from five

and eighty-one hundredths

5. n - 6.47 = 4.32

3.11 Adding and Subtracting Money

How can the strategy make a table help

you organize and keep track of your bank

account balance?

1. Sara wants to buy a bottle of apple juice from a vending machine. She needs exactly $2.30. She

has the following bills and coins:

Make and complete a table to find all the ways Sara

could pay for the juice. First, draw a table with a

column for each type of bill or coin. Next, fill in your

table with each row showing a different way Sara can

make exactly $2.30.

$1 Qtrs Dimes Nickel

s

Value

3.11 Cont’d

2. Mr. and Mrs. Daniels are going to Tokyo next summer. Each week they record

the value of one Yen in U.S. dollars, The table shows the data she has recorded

so far.

For which two weeks was the value of 1 Yen the same when rounded to the

nearest hundredth?

Week Value of 1 Yen (in

U.S.

1 0.096

2 0.091

3 0.099

4 0.089

3.12 Continued

2. 4.19 + 0.58

3. 38.44 − 25.86

4. 5.7 + 2.25 + 1.3

Metric Conversions - K.H.D. (B) D.C.M.

Kilo- x 1000

Hecto- x 100

Deca- x 10

Base (meter, liter, gram) x 1

Deci- x 1/10

Centi- x 1/100

Milli- x 1/1000

Flocabulary Song https://www.flocabulary.com/unit/metric-system/video/

https://www.flocabulary.com/unit/metric-system/video/

Metric conversions - Your Turn