I’ve long regretted the demise of the ‘British’ billion 1012, a million million, in favour of the US version which is 109, a thousand million. It means that the prefixes bi (billion), tri (trillion=million million million), quad (quadrillion) etc no longer make much sense. The change in the system is apparently due to the US adopting the French system (though France and French-speaking parts of North America changed again from 1948); international trade then did the rest. It’s all clearly explained at A Zillion Troubles (thanks to Gooseania for the link).
I sometimes ask my students to think about the size of numbers like a million and a billion (either version) by asking them to guess how long it would take to count to them at the rate of one per second without a break. Then they work it out on a calculator and 99% of their guesses are wildly out 😕