OK, so writing numbers in English is simple enough, right? There is one more thing that causes problems with numbers in English, particularly for German speakers.

Think about the following numbers. How would you say them out loud in English and in German?

100 = one hundred / ein Hundert
1,000 = one thousand / ein Tausend
1,000,000 = one million / ein Million

Easy enough so far, right? But what about:

1,000,000,000

In German, you would say "ein Milliarde", right? Well, in English this is already "a billion". Take a look below and notice what happens:

1,000,000,000 = one billion / ein Milliarde
1,000,000,000,000 = one trillion / ein Billion
1,000,000,000,000,000 = one quadrillion / ein Billiarde
1,000,000,000,000,000,000 = one quintrillion / ein Trillion

Do you notice it? The simplest thing to say here is that one billion is not the same as ein Billion, just as one trillion is not the same as ein Trillion, and so on. Though there isn't a big chance of you having to use such big numbers actively, it's very useful to be aware of this minor difference between English and German.