Grade by Grade
B. Number · Number Sense: Big Numbers, Square Roots and Rational Numbers

Reading and Writing Numbers to One Billion

B1.1 A1About 40 minutes
Learning goals
  • I can read and write whole numbers up to one billion in standard form and in words.
  • I can name the place and the value of any digit in a number up to one billion.
  • I can use periods (ones, thousands, millions) to read big numbers.
  • I can break apart a big number in different ways, like 725 000 000 = 725 millions.

Words to know

period
A group of three places in a number: the ones period, the thousands period, the millions period.
million
1 000 000. One thousand thousands.
billion
1 000 000 000. One thousand millions.
standard form
A number written with digits, like 316 052 400.
place value
The value a digit has because of where it is in the number.

Remember from Grade 6

In Grade 6 you read, wrote and built whole numbers up to one million (1 000 000). You used a place value chart and the "times 10" pattern: each place is worth 10 times the place to its right.

In Grade 7 the numbers get a thousand times bigger. You will work with numbers up to one billion (1 000 000 000).

How long is a billion?

Here is a way to feel how big these numbers are.

  • One thousand seconds is about 17 minutes.
  • One million seconds is about 11 and a half days.
  • One billion seconds is about 32 years!

A million and a billion sound alike, but a billion is 1000 times as big as a million. That is why it matters to read big numbers carefully.

1 000 seconds≈ 17 minutes1 000 000 seconds≈ 11½ days1 000 000 000 seconds≈ 32 years× 1000× 1000(boxes not to scale)
Each step is 1000 times bigger: a thousand seconds is a coffee break, a million seconds is a long vacation, and a billion seconds is about 32 years.

Periods: groups of three

Big numbers are split into groups of three digits called periods. We leave a small space between periods so the number is easy to read.

  • The ones period: hundreds, tens, ones
  • The thousands period: hundred thousands, ten thousands, thousands
  • The millions period: hundred millions, ten millions, millions
  • One billion starts the billions period.

Every period has the same pattern: hundreds, tens, ones.

5H0T7Omillions periodfive hundred seven million3H4T0Othousands periodthree hundred forty thousand0H2T6Oones periodtwenty-sixH = hundreds, T = tens, O = ones: every period has the same pattern
Read 507 340 026 one period at a time: say the three-digit number, then the period name. The ones period gets no name at the end.
BillionsHundred millionsTen millionsMillionsHundred thousandsTen thousandsThousandsHundredsTensOnes
507340026
1000000000
Top row: 507 340 026. Bottom row: 1 000 000 000 (one billion).

How to read a big number

  1. Start at the left.
  2. Read the three-digit number in each period, then say the period name (million, thousand). Don't say "ones" for the last period.
  3. Skip a period that is all zeros.

507 340 026 is read "five hundred seven million three hundred forty thousand twenty-six".

We do not say "and" when reading whole numbers. In math, "and" is saved for the decimal point.

Worked example

Example 1: Read a big number

Read 316 052 400 in words.

  1. Split into periods: 316 | 052 | 400.
  2. Millions period: 316 → "three hundred sixteen million".
  3. Thousands period: 052 → "fifty-two thousand".
  4. Ones period: 400 → "four hundred".

Three hundred sixteen million fifty-two thousand four hundred.

Worked example

Example 2: Write a number from words

Write forty million six thousand ninety in standard form.

  1. Millions period: forty → 040, so the number starts 40.
  2. Thousands period: six thousand → 006. Every period needs three digits, so use zeros as placeholders.
  3. Ones period: ninety → 090.

40 006 090

Worked example

Example 3: Break apart a big number

How many millions and how many thousands are in 725 000 000?

  1. Cover the last six digits (the thousands and ones periods). You see 725, so there are 725 millions.
  2. Cover the last three digits. You see 725 000, so there are 725 000 thousands.

725 000 000 = 725 millions = 725 000 thousands.

Use zeros as placeholders

When you write a number from words, think of each period as a box with three seats. Fill empty seats with zeros. "Six million forty" is 6 | 000 | 040 = 6 000 040, not 6040.

Hands-on activity

Big number builder

You need: 10 small slips of paper, a pencil and a grown-up or sibling.

  1. Write the digits 0 to 9 on the slips, one digit per slip. Turn them face down and mix them.
  2. Draw 9 slips. Use them to build the greatest 9-digit number you can. Write it with spaces between the periods.
  3. Read it aloud. Your partner writes down what they hear. Do the two numbers match?
  4. Now build the least 9-digit number with the same slips. (A 9-digit number can't start with 0!)
  5. Switch roles: your partner builds, you write.

What to look for: the greatest number has the digits from greatest to least, like 987 654 321 if 0 was the slip left over. The least number puts the digits from least to greatest, except that 0 can't go first: if you drew the 0, start with the smallest other digit and put the 0 second (like 102 345 678).

Math talk: "Which digit did you put first? Why?"

Just for fun

If you counted to one billion out loud, one number every second, with no breaks for sleep, it would take you more than 32 years. Better pack a lot of snacks!

Your turn

1

Write 48 305 000 in words.

2

Write two hundred six million seventy thousand fifteen in standard form.

3

What is the value of the 9 in 493 120 000?

4

Which digit is in the hundred millions place in 857 064 312?

5

How many millions are in 625 000 000?

6

How many millions make one billion?

7

Write one billion in standard form. How many zeros does it have?

More practice: warm-up

1

Write 7 000 000 in words.

2

What number is 30 000 000 + 5 000 000?

3

Which digit is in the ten millions place in 564 218 903?

4

Write eighty million in standard form.

5

How many zeros are in one hundred million?

More practice: on your own

1

Write 904 060 007 in words.

2

Write three hundred million four thousand in standard form.

3

What number is 10 million more than 395 200 000?

4

How many thousands are in 72 500 000?

5

Kai wrote "six million forty" as 6040. What is wrong? Write it correctly.

Challenge

1

One year is about 31 500 000 seconds. Is one billion seconds closer to 3 years, 30 years or 300 years? Explain.

2

Use the digits 1 to 9 once each. Make the greatest 9-digit number that has a 5 in the millions place.

3

A 9-digit number has a 4 in the hundred millions place, a 7 in the ten thousands place and a 2 in the ones place. Every other digit is 0. Write it in standard form and in words.

Check your understanding

Quiz

1.

How do you write twelve million five hundred thousand?

2.

How many zeros are in one billion?

3.

What is the value of the 3 in 836 400 000?

4.

One billion is equal to...

5.

How do you read 205 000 017?

6.

Which number is 10 million more than 482 000 000?

For parents and teachers

Big idea: Ontario's Grade 7 curriculum (B1.1) asks students to represent and compare whole numbers up to and including one billion and describe how they are used in everyday life. In Grade 6 your child worked to one million, so the new part is the millions period and one billion.

Common difficulties:

  • Leaving out placeholder zeros (writing "six million forty" as 6040). Remind your child that every period after the first needs three digits.
  • Saying "and" in whole numbers ("two hundred and five million"). It is a small thing, but in math "and" means the decimal point.
  • Mixing up a million and a billion. The seconds comparison (11 days vs. about 32 years) helps.

How to help: Play the big number builder game. When you see big numbers in the news, ask your child to read them aloud. This lesson also builds A1 skills: explaining thinking clearly and checking a partner's work kindly.