This page contains a number of answers to questions that you might have about Numbery.
You can easily turn hyphenation on or off from the main screen. Tap on Settings and then Converter Settings and the option is there.
In the US, numbers are often written without ‘and’ or commas, whereas in other parts of the English-speaking world, they are used. Other than that, the numbers should be the same.
To see the conversion results on the Apple Watch version of Numbery, you have to scroll past the keyboard.