## Envision Math 6th Grade Textbook Answer Key Topic 1.1 Place Value

Review What You Know

Vocabulary
Choose the best term from the box, Question 1.
A period placed in a number to separate whole number values from values less than one is called a ? .
decimal point
Explanation:

Question 2.
The value of the position of any digit in a number is called its ? .
place
Explanation:

Question 3.
The symbols used to write numbers 0, 1,2 3, 4, 5, 6, 7, 8, and 9 are ? .
digits
Explanation: Writing Numbers
Write each word form in standard form.
Question 4.
nineteen
19
Explanation:

Question 5.
thirty-seven
37
Explanation:

Question 7.
two thousand twelve
2,012
Explanation:

Question 8.
forty thousand
40,000
Explanation:

Question 9.
one hundred thousand
100, 000
Explanation:

Write the word form of each number.
See margin
Explanation:

Question 10.
49

Question 11.
112

Question 12.
10,465

Decimals
Writing to Explain Write an answer for the question. Question 13.
How would you locate 3.33 on the number line? Explain.
See margin.
Explanation:

Place Value

How can you read very large numbers?
In astronomy, a light-year is the distance that light can travel in one year. One light-year is equal to about 9,500,000,000,000 kilometers. Use a place-value chart to help you find the value of the digit 9 and read the number. Another Example
What are different ways to write very large numbers?
A place-value chart can help you write a very large number, such as 44,600,000,000, in different forms. Standard form: 44,600,000,000
Word form: forty-four billion, six hundred million
Short word form: 44 billion, 600 million
Expanded form: 40,000,000,000 + 4,000,000,000 + 600,000,000 or
(4 × 10,000,000,000) + (4 × 1,000,000,000) + (6 × 100,000,000)

Explain It
Question 1.
What is the relationship between the commas in a number and the periods in a place-value chart?
See margin.
Explanation:

Question 2.
In the example above, how do you know what the addends are for a number written in expanded form?
See margin.
Explanation: You can use the word form to read the number.
Word form: nine trillion, five hundred billion

Guided Practice

Do you know HOW?
In 1 through 4, write the place and value of the underlined digit.
Question 1.
1,234,567
See margin.
Explanation: Question 2.
9,870,563,142,000

Question 3.
36,192,748
See margin
Explanation:

Question 4.
82,765,432,109,497

In 5 and 6, write each number in the form indicated.
Question 5.
57,000,000,009 in expanded form
See margin.
Explanation:

Question 6.
321 trillion, 705 thousand in standard form
See margin.
Explanation:

Do you UNDERSTAND?
Question 7.
How do you use periods to read and write very large numbers?
See margin.
Explanation:

Question 8.
In the example at the top, how would you write the number in expanded form?
See margin.
Explanation:

Question 9.
When writing 136,000,000 in expanded form, why would you skip the hundred thousands, ten thousands, thousands, hundreds, tens, and ones?
Those places are occupied by zeros.
Explanation:

Independent Practice

In 10 through 12, write the place and value of the digit 3 in each number?
See margin.
Explanation:
Question 10.
3,476 Question 11.
384,400

Question 12.
5,437,200,184,400

In 13 through 15, write each number in short-word form.
See margin.
Explantion:

Question 13.
18,429,000,050,000

Question 14.
10,007,000,000,000

Question 15.
8,507,004,041

For 16 through 19, use the number 1,435,600,000,000.
Question 16.
What is the place and value of the digit 5? billions,
5,000,000,000
Explanation:

Question 17.
What is the value of the digit 3?
30,000,000,000
Explanation:

Question 18.
Write the number in word form.
One trillion, four hundred thirty-five billion, six hundred million

Question 19.
Using both multiplication and addition, how would you write this number in expanded form?
See margin.
Explanation:

Problem Solving

Question 20.
How do you write the number of stars in the Milky Way galaxy in standard form?
200,000,000,000
Explanation:

Question 21.
Writing to Explain Describe how you would use the standard form of a number to write the short-word form.
See margin.
Explanation:

In a recent year, the world used an estimated 15,850,000,000 kilowatt hours of electricity. Use this information to answer 22 through 24. Question 22.
What is the value of each non-zero digit in the number
10,000,000,000; 5,000,000,000; 800,000,000; 50,000,000
Explanation:

Question 23.
Number Sense From left to right, what is the place of the second 5 in this number?
A. trillions
B. hundred millions
C. ten millions
D. hundred thousands
C. ten millions
Explanation:

Question 24.
Algebra At this rate, how many kilowatt hours of electricity might the world use over a 10-year period?
A. 160 million
B. 160 billion
C. 16 trillion
D. 160 trillion
B. 160 billion
Explanation:

Question 25.
Which of these numbers represents seventy-six trillion, two hundred seven thousand?
A. 76,000,000,207,000
B. 76,000,000,007,200
C. 76,000,207,000,000
D. 76,000,207,000
A. 76,000,000,207,000
Explanation:

Question 26.
Which of these numbers is ten million more than three billion, four hundred twenty-nine million?
A. 3,419,000,000,000
B. 3,439,000,000,000
C. 3,419,000,000
D. 3,439,000,000
D. 3,439,000,000
Explanation:

Mixed Problem Solving

Ancient Civilizations in Today’s World Use the estimated populations shown on the map above to answer 1 through 10.
Question 1.
Which countries have a population in the billions?
India and China
Explanation:

Question 2.
Which value does the digit 1 have in Greece’s population?
10 million
Explanation:

Question 3.
Which places does the digit 3 occupy in China’s population?
Hundred millions, millions, thousands, and ones
Explanation:

Question 4.
Which country has a population close to 80 million?
Egypt
Explanation:

Question 5.
Which countries have a population between ten million and one hundred million?
Greece, Egypt, and Italy
Explanation:

Question 6.
Draw a place-value chart to show the place and value of each of the digits in I ndia’s population.
Place-value chart should show 1,095,351,995.
Explanation:

Question 7.
Which country has the least population? 8. How much less is its population than the greatest population shown?
Greece; 1,303,285,655
Explanation:

Question 8.
How many people would India need to gain for its population to equal that of China?
218,621,718
Explanation:

Question 9.
In a recent year, the population of Italy’s 10. capital, Rome, was about 2,553,873. About how many times larger was Italy’s population than the population of Rome?