## 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 ? .

Answer:

decimal point

Explanation:

Question 2.

The value of the position of any digit in a number is called its ? .

Answer:

place

Explanation:

Question 3.

The symbols used to write numbers 0, 1,2 3, 4, 5, 6, 7, 8, and 9 are ? .

Answer:

digits

Explanation:

**Writing Numbers**

Write each word form in standard form.

Question 4.

nineteen

Answer:

19

Explanation:

Question 5.

thirty-seven

Answer:

37

Explanation:

Question 7.

two thousand twelve

Answer:

2,012

Explanation:

Question 8.

forty thousand

Answer:

40,000

Explanation:

Question 9.

one hundred thousand

Answer:

100, 000

Explanation:

Write the word form of each number.

Answer:

See margin

Explanation:

Question 10.

49

Answer:

Question 11.

112

Answer:

Question 12.

10,465

Answer:

**Decimals**

Writing to Explain Write an answer for the question.

Question 13.

How would you locate 3.33 on the number line? Explain.

Answer:

See margin.

Explanation:

**Place Value**

How can you read very large numbers?

Answer:

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?

Answer:

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?

Answer:

See margin.

Explanation:

Question 2.

In the example above, how do you know what the addends are for a number written in expanded form?

Answer:

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

Answer:

See margin.

Explanation:

Question 2.

9,870,563,142,000

Answer:

Question 3.

36,192,748

Answer:

See margin

Explanation:

Question 4.

82,765,432,109,497

Answer:

In 5 and 6, write each number in the form indicated.

Question 5.

57,000,000,009 in expanded form

Answer:

See margin.

Explanation:

Question 6.

321 trillion, 705 thousand in standard form

Answer:

See margin.

Explanation:

**Do you UNDERSTAND?**

Question 7.

How do you use periods to read and write very large numbers?

Answer:

See margin.

Explanation:

Question 8.

In the example at the top, how would you write the number in expanded form?

Answer:

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?

Answer:

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?

Answer:

See margin.

Explanation:

Question 10.

3,476

Answer:

Question 11.

384,400

Answer:

Question 12.

5,437,200,184,400

Answer:

In 13 through 15, write each number in short-word form.

Answer:

See margin.

Explantion:

Question 13.

18,429,000,050,000

Answer:

Question 14.

10,007,000,000,000

Answer:

Question 15.

8,507,004,041

Answer:

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,

Answer:

5,000,000,000

Explanation:

Question 17.

What is the value of the digit 3?

Answer:

30,000,000,000

Explanation:

Question 18.

Write the number in word form.

Answer:

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?

Answer:

See margin.

Explanation:

**Problem Solving**

Question 20.

How do you write the number of stars in the Milky Way galaxy in standard form?

Answer:

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.

Answer:

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

Answer:

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

Answer:

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

Answer:

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

Answer:

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

Answer:

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?

Answer:

India and China

Explanation:

Question 2.

Which value does the digit 1 have in Greece’s population?

Answer:

10 million

Explanation:

Question 3.

Which places does the digit 3 occupy in China’s population?

Answer:

Hundred millions, millions, thousands, and ones

Explanation:

Question 4.

Which country has a population close to 80 million?

Answer:

Egypt

Explanation:

Question 5.

Which countries have a population between ten million and one hundred million?

Answer:

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.

Answer:

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?

Answer:

Greece; 1,303,285,655

Explanation:

Question 8.

How many people would India need to gain for its population to equal that of China?

Answer:

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?

Answer:

About 20 times larger

Explanation:

Question 10.

It is projected that China’s population will increase approximately 20% by 2025. Approximately how many more people will China have?

A. 130,000,000

B. 89,000,000

C. 260,000,000

D. 3,190,000,000

Answer:

C. 260,000,000

Explanation: