A blog about teaching and learning in a maths classroom.

Million, billion, trillion

Thursday, 12 March 2009 | 3 Comments

I used to think that I knew what 1 billion was, i.e. 1 000 000 000 000. Then a couple of years ago, I looked on Wikipedia and found there were two defintions: Long and short scales.

It seems that changes in the way Australia defines one billion have only occurred relatively recently (quoting Wikipedia)

As of 1999, the Australian Government’s financial department did not consider short scale to be standard, but used it occasionally. The current recommendation by the Australian Department of Finance and Administration (formerly known as AusInfo), and the legal definition, is the short scale.

According to the Metric Conversion page from the National Measurement Institute:

Common usage in Australia (AS/NZX 1376:1996 Conversion Factors, p31) is that:

  • million = 106 (i.e. 1 000 000)
  • billion = 109 (i.e. 1 000 000 000)
  • trillion = 1012 (i.e. 1 000 000 000 000)
  • quadrillion = 1015 (i.e. 1 000 000 000 000 000)

So, it seems that Australia does follow the short scale.

Now that we’ve sorted that out… here are some helpful photos found on the web for understanding large numbers.

This first image is a photo of one billion dollars (US of course).

This second visualization starts with a $100 dollar bill, goes to $10 000, $1 million, $100 million, $1 billion (pictured below) and then $1 trillion.

Click through both photos for a better version.

A couple of notes:

Posted in • Lesson IdeaNumberMediaPhoto | Short URL:


Liz on  12 March 09  at  01:42 PM #
i was of the understanding that a billion in australia and england was a million million and that in usa was a thousand million so being a billionaire in america was more common


Simon Job on  13 March 09  at  04:44 AM #
Me too, but it seems that has changed - hence this post. Looking in a couple of Year 7 textbooks: "New Century Maths 7": billion = 1 000 000 000 "MathScape 7": 1 billion = 1 thousand million = 1000000000 So, the text book writers got the memo of the change.
Tim on  14 April 09  at  01:03 PM #
Perhaps this is more of a language issue than a maths issue. My high school dictionary has both definitions of a billion. The foreign language dictionaries I checked only went up to a million.

Post a comment

Commenting is not available in this channel entry.

New  Subscribe to the …

email newsletter

Get updates…

Twitter   Facebook   Pinterest


Simon Job — eleventh year of teaching maths in a public high school in Western Sydney, Australia.
MathsClass is about teaching and learning in a maths classroom. more→


by date

by category


updates via @mathslinks

Recently read/found.

View All | RSS