Lesson 1
What Is a Thousandth?
— Journal Prompt: One Thousandth (1 problem)
What did you learn about 1 thousandth? What do you still wonder about 1 thousandth?
Show Solution Sample responses: One thousandth can be represented on a grid. It can be written as 0.001. It's really small. It is one tenth of one hundredth. I wonder if there is something smaller than 1 thousandth.
Lesson 2
Thousandths on Diagrams and in Words
— Shading Thousandths (1 problem)
Shade the grid to represent 0.149.
What is another way you could represent 0.149?
Show Solution
Sample responses:
One tenth, four hundredths, and nine thousandths
One hundred forty-nine thousandths
149 1 , 000 \frac{149}{1,000} 1 , 000 149
Lesson 3
Thousandths in Expanded Form
— Different Ways to Write a Decimal Number (1 problem)
The shaded region of the diagram shows a number.
Write the number as a decimal.
Write the number as a fraction.
Write the number in expanded form.
Write the number in word form.
Show Solution
0.579
579 1 , 000 \frac{579}{1,000} 1 , 000 579
( 5 × 0.1 ) + ( 7 × 0.01 ) + ( 9 × 0.001 ) \left(5 \times 0.1\right) + \left(7 \times 0.01\right) + \left(9 \times 0.001\right) ( 5 × 0.1 ) + ( 7 × 0.01 ) + ( 9 × 0.001 )
five hundred seventy-nine thousandths
Lesson 4
Explore Place Value Relationships
— Worth its Weight in Gold (1 problem)
A gold nugget balances with 2 one hundredth ounce weights and 6 one thousandth ounce weights.
What is the weight of the nugget? Write your answer as a decimal.
What is a different set of weights that will balance the nugget?
Show Solution
0.026 ounces
Sample response: One hundredth ounce and 16 thousandth ounce weights, because a hundredth is the same as 10 thousandths.
Lesson 5
Compare Decimals
— Compare Decimals (1 problem)
Lin threw the disc 5.09 meters. Andre threw the disc 5.1 meters. Who threw the disc farther? Explain or show your reasoning.
Show Solution Andre. Sample response: They each threw it 5 meters but then 1 tenth is 10 hundredths and that's more than 9 hundredths.
Lesson 6
Compare Decimals on the Number Line
— Locate, Label, and Compare Numbers (1 problem)
Locate and label 0.355 and 0.359 on the number line.
Which is greater, 0.355 or 0.359? Explain or show your reasoning.
Show Solution
0.359 is greater. Sample response: It's farther to the right.
Lesson 7
Round Doubloons
— A Golden Dollar (1 problem)
A one-dollar gold coin weighs 1.672 grams.
A scale measures weights to the nearest tenth of a gram. What will the scale read for the weight of this coin?
A different scale measures weights to the nearest hundredth of a gram. What will the scale read for the weight of this coin?
Show Solution Lesson 8
Round Decimals
— Round to the Nearest Tenth and Hundredth (1 problem)
Round 17.637 to the nearest tenth. Use the number lines if they are helpful.
Round 17.637 to the nearest hundredth. Use the number lines if they are helpful.
Show Solution Lesson 9
Order Decimals
— Order the Decimals (1 problem)
Write these numbers in order from least to greatest: 565.4, 556.040, 565.004
Show Solution 556.040, 565.004, 565.4
Lesson 10
Solve Problems with Decimals
— Luge Rider (1 problem)
A luge rider finished a race in 49.256 seconds. Determine the time rounded to the nearest tenth and hundredth of a second.
Show Solution
Nearest tenth: 49.3 seconds
Nearest hundredth: 49.26 seconds
Section A Check
Section A Checkpoint
Problem 1
Select all representations of 0.631.
Show Solution B, D, E
Problem 2
Order the following decimals from least to greatest.
0.439
0.394
0.441
0.531
0.342
Show Solution 0.342, 0.394, 0.439, 0.441, 0.531
Problem 3
Answer the following questions about rounding 13.728. Explain or show your reasoning. Use the number line if it is helpful.
What is 13.728 rounded to the nearest hundredth
What is 13.728 rounded to the nearest tenth?
Show Solution
13.7. Sample response: It is between 13.7 and 13.8 and is closer to 13.7 than to 13.8.
13.73. Sample response: It is between 13.72 and 13.73 and is closer to 13.73 than to 13.72.
Lesson 11
Make Sense of Decimal Addition
— The Value of the Sum (1 problem)
What is the value of 1.20 + 0.13 1.20 + 0.13 1.20 + 0.13 ? Explain or show your reasoning.
Show Solution 1.33. Sample responses:
1.20 + 0.10 = 1.30 1.20 + 0.10 = 1.30 1.20 + 0.10 = 1.30 ,
1.30 + 0.03 = 1.33 1.30 + 0.03 = 1.33 1.30 + 0.03 = 1.33 Lesson 12
Estimate and Add
— Sums of Decimals (1 problem)
Find the value of 3.45 + 21.6 3.45 + 21.6 3.45 + 21.6 . Explain or show your reasoning.
Show Solution 25.05. Sample responses:
21 + 3 = 24 21+3=24 21 + 3 = 24 , 0.40 + 0.60 = 1.00 0.40+0.60=1.00 0.40 + 0.60 = 1.00 , 24 + 1 = 25 24+1=25 24 + 1 = 25 , 25 + 0.05 = 25.05 25+0.05=25.05 25 + 0.05 = 25.05
Lesson 13
Analyze Addition Mistakes
— What is the Error? (1 problem)
The calculation below has an error.
Explain the error.
Find the correct value of 38.7 + 9.46 38.7 + 9.46 38.7 + 9.46 .
Show Solution
Sample response: The decimal places are not lined up so the 30 in 38.7 is treated like it's only 3.
48.16. Sample response:
Lesson 14
Make Sense of Decimal Subtraction
— Subtract (1 problem)
Find the value of 3.57 − 1.4 3.57 - 1.4 3.57 − 1.4 . Explain or show your reasoning.
Show Solution 2.17. Sample response: 3 − 1 = 2 3-1=2 3 − 1 = 2 , 0.57 − 0.40 = 0.17 0.57-0.40=0.17 0.57 − 0.40 = 0.17 , 2.00 + 0.17 = 2.17 2.00+0.17=2.17 2.00 + 0.17 = 2.17
Lesson 15
Estimate and Subtract
— Subtract Decimals (1 problem)
Find the value of 321.87 – 20.4 321.87 – 20.4 321.87–20.4 . Explain or show your reasoning.
Show Solution 301.47. Sample responses:
321 − 20 = 301 321 - 20 = 301 321 − 20 = 301 , 0.8 − 0.4 = 0.4 0.8 - 0.4 = 0.4 0.8 − 0.4 = 0.4 , 0.07 − 0 = 0.07 0.07 - 0 = 0.07 0.07 − 0 = 0.07 , 301 + 0.4 + 0.07 = 301.47 301+0.4+0.07=301.47 301 + 0.4 + 0.07 = 301.47
Lesson 16
Addition and Subtraction
— Add and Subtract Decimals (1 problem)
Find the value of each expression. Explain or show your reasoning.
75.2 − 4.37 75.2 - 4.37 75.2 − 4.37
236.87 + 5.15 236.87 + 5.15 236.87 + 5.15
Show Solution
70.83. Sample response:
242.02. Sample response: 236.87 + 0.13 = 237 236.87+0.13=237 236.87 + 0.13 = 237 , 237 + 5.02 = 242.02 237+5.02=242.02 237 + 5.02 = 242.02
Section B Check
Section B Checkpoint
Problem 1
Priya ran 1.9 miles on Saturday, and 2.34 miles on Sunday. How many miles did she run altogether? Explain or show your reasoning.
Show Solution 4.24 miles. Sample response: 1.9 + 2 = 3.9 1.9 + 2 = 3.9 1.9 + 2 = 3.9 , 3.9 + 0.3 = 4.2 3.9 + 0.3 = 4.2 3.9 + 0.3 = 4.2 , 4.2 + 0.04 = 4.24 4.2 + 0.04 = 4.24 4.2 + 0.04 = 4.24
Problem 2
Find the value of each expression. Explain or show your reasoning.
12.1 + 5.77 12.1 + 5.77 12.1 + 5.77
1 − 0.15 1 - 0.15 1 − 0.15
38.12 − 27.3 38.12 - 27.3 38.12 − 27.3
Show Solution
17.87. Sample response: 12.1 + 5 = 17.1 12.1 + 5 = 17.1 12.1 + 5 = 17.1 , 17.1 + 0.77 = 17.87 17.1 + 0.77 = 17.87 17.1 + 0.77 = 17.87
0.85. Sample response: 0.15 + 0.05 = 0.2 0.15 + 0.05 = 0.2 0.15 + 0.05 = 0.2 , 0.2 + 0.8 = 1 0.2 + 0.8 = 1 0.2 + 0.8 = 1 , 0.05 + 0.8 = 0.85 0.05 + 0.8 = 0.85 0.05 + 0.8 = 0.85
10.82. Sample response:
Lesson 17
Multiply Decimals and Whole Numbers
— Multiply a Decimal by a Whole Number (1 problem)
Find the value of each expression. Explain or show your reasoning.
2 × 0.4 2 \times 0.4 2 × 0.4
4 × 0.03 4 \times 0.03 4 × 0.03
Show Solution
0.8. Sample response: 0.4 is 4 tenths and double that is 8 tenths or 0.8.
0.12. Sample response: 0.03 is 3 hundredths and 4 groups of 3 hundredths is 12 hundredths or 0.12.
Lesson 18
Use Whole Number Facts
— Fill in the Blank (1 problem)
Fill in the blank to make each equation true.
5 × 0.3 = 5 × 3 × ‾ 5 \times 0.3 = 5 \times 3 \times \underline{\hspace{0.9cm}} 5 × 0.3 = 5 × 3 ×
5 × 0.03 = 5 × ‾ × 0.01 5 \times 0.03 = 5 \times \underline{\hspace{0.9cm}} \times 0.01 5 × 0.03 = 5 × × 0.01
5 × 0.03 = ‾ 5 \times 0.03 = \underline{\hspace{0.9cm}} 5 × 0.03 =
Show Solution Lesson 19
Use Properties to Multiply Decimals
— Interpret Expressions (1 problem)
Select all the expressions that are equivalent to 15 × 0.19 15 \times 0.19 15 × 0.19 .
15 × 19 × 0.01 15 \times 19 \times 0.01 15 × 19 × 0.01
( 15 × 0.1 ) + ( 15 × 0.09 ) (15 \times 0.1) + (15 \times 0.09) ( 15 × 0.1 ) + ( 15 × 0.09 )
15 × 19 × 0.1 15 \times 19 \times 0.1 15 × 19 × 0.1
( 15 × 0.2 ) − ( 15 × 0.01 ) (15 \times 0.2) - (15 \times 0.01) ( 15 × 0.2 ) − ( 15 × 0.01 )
Choose one expression to find the value of 15 × 0.19 15 \times 0.19 15 × 0.19 .
Show Solution
A, B, and D
Sample response: 15 × 0.2 15 \times 0.2 15 × 0.2 is 30 tenths or 3 and 15 × 0.01 15 \times 0.01 15 × 0.01 is 15 hundredths or 0.15. Then 3 − 0.15 = 2.85 3 - 0.15 = 2.85 3 − 0.15 = 2.85 .
Lesson 20
Products in the Hundredths Place
— Tenths (1 problem)
Find the value of each expression. Use the diagrams if they are helpful.
0.3 × 0.6 0.3 \times 0.6 0.3 × 0.6
1.3 × 0.6 1.3 \times 0.6 1.3 × 0.6
Show Solution
0.18 (or equivalent)
0.78 (or equivalent)
Lesson 21
Multiply More Decimals
— Why Expressions Have the Same Value (1 problem)
Explain why 2.5 × 6.4 2.5 \times 6.4 2.5 × 6.4 and ( 25 × 64 ) × 0.01 (25 \times 64) \times 0.01 ( 25 × 64 ) × 0.01 have the same value.
Find the value of 2.5 × 6.4 2.5 \times 6.4 2.5 × 6.4 .
Show Solution
Sample response: 2.5 = 25 × 0.1 2.5 = 25 \times 0.1 2.5 = 25 × 0.1 and 6.4 = 64 × 0.1 6.4 = 64 \times 0.1 6.4 = 64 × 0.1 so 2.5 × 6.4 = ( 25 × 64 ) × 0.01 2.5 \times 6.4 = (25 \times 64) \times 0.01 2.5 × 6.4 = ( 25 × 64 ) × 0.01
16. Sample response: 25 × 64 = 1 , 600 25 \times 64 = 1,600 25 × 64 = 1 , 600 so 2.5 × 6.4 = 16.00 2.5 \times 6.4 = 16.00 2.5 × 6.4 = 16.00
Section C Check
Section C Checkpoint
Problem 1
Find the value of the expression 0.3 × 0.5 0.3 \times 0.5 0.3 × 0.5 . Explain or show your reasoning. Use the grid if it is helpful.
Show Solution 0.15. Sample response: There are 15 shaded parts and each one is 0.01.
Problem 2
To find the value of 0.28 × 37 0.28 \times 37 0.28 × 37 Andre calculates 28 × 37 28 \times 37 28 × 37 and then multiplies by 0.01. Explain or show why Andre's strategy works and use it to find the value of 0.28 × 37 0.28 \times 37 0.28 × 37 .
Show Solution 10.36. Sample response: Since 0.28 is 28 hundredths, I can multiply 28 and 37 and then multiply that by 0.01. Since 28 × 37 = 1 , 036 28 \times 37 = 1,036 28 × 37 = 1 , 036 , 0.28 × 37 0.28 \times 37 0.28 × 37 is 10.36 10.36 10.36 .
Problem 3
Find the value of the expression
2.1 × 7.3 2.1 \times 7.3 2.1 × 7.3 . Explain or show your reasoning.
Show Solution 15.33. Sample response: I first found 21 × 73 21 \times 73 21 × 73 which is 1 , 533 1,533 1 , 533 . Then I multiply that by 0.1 twice since 2.1 = 21 × 0.1 2.1 = 21 \times 0.1 2.1 = 21 × 0.1 and 7.3 = 73 × 0.1 7.3 = 73 \times 0.1 7.3 = 73 × 0.1 . That gives 15.33 15.33 15.33 .
Lesson 22
Divide Whole Numbers by 0.1 and 0.01
— Many Tenths and Hundredths (1 problem)
Find the value of each expression. Explain or show your reasoning.
7 ÷ 0.1 7 \div 0.1 7 ÷ 0.1
7 ÷ 0.01 7 \div 0.01 7 ÷ 0.01
Show Solution
70. Sample response: 1 ÷ 0.1 = 10 1 \div 0.1 = 10 1 ÷ 0.1 = 10 and 7 × 10 = 70 7 \times 10 = 70 7 × 10 = 70
700. Sample response: There are 100 hundredths in 1, so there are 700 hundredths in 7.
Lesson 23
Divide Whole Numbers by Decimals
— Divide Whole Numbers by Decimals (1 problem)
Find the value of each expression. Explain or show your reasoning.
12 ÷ 0.5 12 \div 0.5 12 ÷ 0.5
13 ÷ 0.02 13 \div 0.02 13 ÷ 0.02
Show Solution
24. Sample response: There are 2 groups of 0.5 in 1 whole and 12 × 2 = 24 12 \times 2=24 12 × 2 = 24 .
650. Sample responses:
There are 50 groups of 0.02 in 1. Since there are 13 wholes, that means there will be 13 times as many 0.02s which is the same as 13 groups of 50.
50 × 0.02 = 1 50 \times 0.02=1 50 × 0.02 = 1 , 500 × 0.02 = 10 500 \times 0.02 = 10 500 × 0.02 = 10 , 100 × 0.02 = 2 100\times 0.02=2 100 × 0.02 = 2 and 50 × 0.02 = 1 50 \times 0.02 = 1 50 × 0.02 = 1 so ( 500 + 100 + 50 ) × 0.02 = 10 + 2 + 1 = 13 (500 + 100 + 50) \times 0.02 = 10 + 2 + 1 = 13 ( 500 + 100 + 50 ) × 0.02 = 10 + 2 + 1 = 13
Lesson 24
Divide Decimals by Whole Numbers
— Divide Decimals by Whole Numbers (1 problem)
Find the value of each expression. Explain or show your reasoning.
0.9 ÷ 3 0.9 \div 3 0.9 ÷ 3
0.09 ÷ 3 0.09 \div 3 0.09 ÷ 3
0.8 ÷ 5 0.8 \div 5 0.8 ÷ 5
Show Solution
0.3. Sample response: There are 9 tenths so that’s 3 groups of 3 tenths.
0.03. Sample response: There are 9 hundredths so that’s 3 groups of 3 hundredths.
0.16. Sample response: There are 80 hundredths so that’s 5 groups of 16 hundredths.
Lesson 25
Divide Decimals by Decimals
— Divide by Decimals (1 problem)
Find the value of each expression. Explain or show your reasoning.
1.6 ÷ 0.01 1.6 \div 0.01 1.6 ÷ 0.01
2.87 ÷ 0.01 2.87 \div 0.01 2.87 ÷ 0.01
Show Solution
160. Sample responses:
1.6 ÷ 0.01 = 160 ÷ 1 1.6 \div 0.01 = 160 \div 1 1.6 ÷ 0.01 = 160 ÷ 1
There are one hundred 0.01s in 1, sixty 0.01s in 0.6, and one hundred sixty 0.01s in 1.6.
287. Sample responses:
2.87 ÷ 0.01 = 287 ÷ 1 2.87 \div 0.01 = 287 \div 1 2.87 ÷ 0.01 = 287 ÷ 1
There are two hundred 0.01s in 2, eighty 0.01s in 0.8, seven 0.01s in 0.07, and two hundred eighty-seven 0.01s in 2.87.
Lesson 26
Book Fair
— Section D Check
Section D Checkpoint
Problem 1
Find the value of 1 ÷ 0.05 1 \div 0.05 1 ÷ 0.05 . Use the diagram if it is helpful.
Show Solution 20. Sample response: I filled in the unit square with groups of 0.05 and there are 20 of them.
Problem 2
Explain how the shaded region of the diagram shows 0.72 ÷ 6 0.72 \div 6 0.72 ÷ 6 .
Find the value of 0.72 ÷ 6 0.72\div6 0.72 ÷ 6 .
Show Solution
Sample response: There is a total of 72 hundredths of the square shaded in the diagram and it is divided into 6 equal groups.
0.12. Sample response: There are 12 hundredths in each of the groups.
Problem 3
Which expression has the same value as 84 ÷ 0.1 84 \div 0.1 84 ÷ 0.1 ?
A. 840 ÷ 0.01 840 \div 0.01 840 ÷ 0.01 B. 840 ÷ 10 840 \div 10 840 ÷ 10 C. 8400 ÷ 1 8400 \div 1 8400 ÷ 1 D. 8.4 ÷ 0.01 8.4 \div 0.01 8.4 ÷ 0.01 ✓ Show Solution D
Unit 5 Assessment
End-of-Unit Assessment