Can I have your number, please?

You'd think telephone numbers would be a simple thing to grasp. Let me tell you, in New Zealand they are not.

American phone numbers are fairly standard across the country, not only in number of digits, but in how they are given out. There's an area code (three numbers), an exchange (three numbers), and an extension (four numbers). When asking for someone's number most people read it out in these groupings, eg 123-456-7890. Here, all bets are off. An area code can be either two or three digits. The actual number can be 6, 7, or 8 digits. That, in itself, is not so difficult to grasp. The problem arises when New Zealanders say their phone number. There is no standard. A simple number like 123-456-7890 could be expressed as 12-34-56-78-90, or 1-23-456-78-90, or 123-45-678-90. You get the idea. The factorial permutations here are astronomical. I've done some serious higher level mathematical studying in my day, but this goes beyond my capabilities. The only pattern I've deciphered is that double numbers are always said together, as in 012 33 456 78 (or 01 2 33 4 5678, or 0 12 33 45 678). If your head is spinning in a haze of numbers at this point, you now understand my misunderstanding. What was that number?