
When is a billion not a billion?
Did you know that the American system for naming large numbers is not the same as the British system? What we call a billion, they call a thousand million. And what they call a billion, we call a trillion! And it continues from there. After a million, we do not agree on any of the names for large numbers. The chart below summarizes the differences.
Number

Power
of 10

American
Name

British
Name

1,000

10^{3}

thousand

thousand

1,000,000

10^{6}

million

million

1,000,000,000

10^{9}

billion

thousand million

1,000,000,000,000

10^{12}

trillion

billion

1,000,000,000,000,000

10^{15}

quadrillion

thousand billion

1,000,000,000,000,000,000

10^{18}

quintillion

trillion

As you can see, Americans name their numbers based on powers of 10 that are multiples of 3, while the British name theirs based on multiples of 6.
Every symbol has a name. Some are better known than others. Here are four of the less wellknown ones. Do you know what they're called? On the left are the symbols along with their common names. On the right are the mathematical names, but not necessarily in the right order. Do you know which goes with which? When you think you know, click on the ANSWER button.


