Big numbers: thousand, million and billion
๐ In short
How many grains of sand on the beach? How many stars in the sky? How many people on Earth? To talk about these huge amounts we need big numbers: thousand, million and billion. They're all built the same way: ten of one place make the next place.
๐คฉ Did you know?
- Counting to a million, one number a second, takes more than 11 days.
- The human body has more than 30,000 billion cells.
- The Sun is about 150 million kilometers from Earth.
- The number โgoogolโ is a one followed by a hundred zeros, and the company Google took its name from it.
๐ Find out more
๐ A thousand
A thousand is ten hundreds, written 1000: a one and three zeros. If you counted from 1 to 1000, one number every second, it would take about 17 minutes.
๐ A million
A million is a thousand thousands, written 1,000,000: a one and six zeros. If you counted to a million, one number a second, without sleeping or eating, it would take more than 11 days!
๐ก A billion
A billion is a thousand millions, written with a one and nine zeros. There are more than 8 billion people on Earth today. And counting to a billion would take more than 31 years!
๐ฏ Reading in groups
To read a big number we split its digits into groups of three, starting from the right: 2,500,000 is read two million five hundred thousand. The gaps between the groups help your eyes.
๐งฎ Worked examples
- 1000 = 10 ร 100A thousand is ten hundreds.
- 1 000 000 = 1000 ร 1000A million is a thousand thousands.
- 3 250 000Three million two hundred and fifty thousand.
๐ Key words
- A thousand
- Ten hundreds: 1000
- A million
- A thousand thousands: 1,000,000
- A billion
- A thousand millions: a one and nine zeros
๐งช Try it at home
Fill a teaspoon with grains of rice and count them. How many spoonfuls do you need to reach a thousand grains? And how many bags to reach a million? Estimate before you calculate!
๐งฉ Test yourself
1 How many zeros are in a million?
2 A thousand isโฆ
3 About how many people live on Earth?