2.1.5 The Decimal System Compared

Activity symbolActivity: Different Countries, Different Methods

Try writing the numerical value for 1 billion using the number system with which you are familiar.

Hint symbol


Your answer will depend on where you live. The system used in English-speaking countries is different from that used in other countries (like France, and Germany). In these other countries, a billion (“bi” meaning two) has twice as many zeros as a million; a trillion (“tri” meaning three) has three times as many zeros as a million, etc.

Note: The scientific community, in general, uses the American system.

Number of ZerosU.S. & Scientific CommunityOther Countries
9billion1000 million (sometimes called 1 milliard)
15quadrillion1000 billion
Solution symbol


In English-speaking countries and the scientific community worldwide, one billion would be written “1,000,000,000.” In some other countries, one billion might be written “1,000,000,000,000.”

notepad symbol Activity: Using Your Math Notebook

Now is a good time to think about how you are using your math notebook. Are you using it to write down any unfamiliar math language? If you have a separate section in your notebook for this you will build up a list of math language—your own glossary of terms that you can look back to at any time if you need a reminder about the meaning of a word or phrase. Try this now with the section that you have just covered.

2.1.4 Numbers in Standard Form

2.2 Using a Number Line