The Milky Way Galaxy

How to write a Billion


Writing big numbers can take a lot of space.

If you write a 1 followed by 3 zeros,
you get 1,000 = one thousand.

If you write a 1 followed by 6 zeros,
you get 1,000,000 = one million.

If you write a 1 followed by 9 zeros,
you get one billion!

It's your turn.
Try writing out one billion in the box below:

Takes time, right? And astronomers often deal with even larger numbers such as a trillion (12 zeros) and a quadrillion (15 zeros). So, when astronomers write numbers with lots of zeros, they use a shorthand called scientific notation. Instead of writing out a 1 followed by 9 zeros, they write a billion like this: 109.

It's your turn to use scientific notation.

How would you write a trillion:
1013 1016 1012

Write a quadrillion here:
1015 1018 1014

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