Additional Math Pages & Resources

Monday, September 7, 2009

What's your number?

Forget the old dating question "What's your sign?"

A more important one is "What's your phone number?"

Of course we won't both tell each other our numbers, one of us will call the other and then our mobile phones will have the numbers.

I have had only one home number since I bought a house in 1976. But I've had 3-4 mobile phone numbers in the USA and 2 in Europe. Then 2 fax numbers, 5 company phone numbers, 2 modem/data numbers and about 7-8 more numbers (in my youth). That makes a total over 20.

And I don't have that many compared to some!  I started to wonder how phone numbers are organized ...

The International Telecommunication Union establishes and maintains a standard for telephone numbers. The ITU is the second-oldest international committee, being established in 1865 to deal with the new telegraph technology. (Similar groups coordinate mail and postage rules, radio and television standards, time-keeping, etc.)

The ITU decided telephone numbers should be no more than 15 digits. Numbers begin with a 1-3 digit country code. When dialed from a mobile phone, international calls always start with a + sign.

Country Codes
Country codes are grouped by geographic area. You don't have to dial the country code when you are within the country, but you do when calling into another country.

  • 1        US, Canada & Carribbean
  • 2        Africa, Atlantic & Indian Ocean Islands
  • 3 / 4   Europe
  • 5        Mexico & Latin America
  • 6        Southeast Asia
  • 7        Russia & Khazakstan
  • 8        East Asia
  • 9        West & Central Asia & Middle East
Area Codes
Here's a list of North America's Area Codes.
Not all area codes are used. Some are reserved for special purposes, such as 

  • 211  Local community information
  • 311  Reserved
  • 411  Information
  • 511  Travel & Traffic Information
  • 555  Directory services (and phony movie phone numbers)
  • 611  Reserved
  • 710  Government
  • 711  Special relays
  • 800, 822, 833, 844, 855, 866, 877, 888 Toll Free numbers
  • 811  Reserved
  • 900  Pay-per-call services
  • 911  Emergency services
  • 999  Reserved

Number Formats
When I lived in England I was always irritated by my phone book software, which formatted numbers according to US standards, NOT the way my friends in the UK stated them or wrote them. And it does make a difference to your ear / hand coordination.
My UK phone number was 07817 421 XXX while my mind was thinking  781 742 XXXX.

At that time the UK numbers varied in the number of digits required, which really threw me for a loop.
And making it even MORE confusing for a caller, when giving their numbers the French (for instance) will NOT say neuf deux (nine two) but quatre vingt douze (four twenties and twelve) for those 2 digits.

And where Americans would say three three three, five five oh two,
a Brit might say treble three, double five nought two

Finally, to make an international call from the USA to the UK, you must remember this process:
Landline dialing to landline:  011 44 (drop the zero) 1932 843 XXX
Mobile dialing to landline:    +44 (drop the zero) 1932 843 XXX
The number formats (of course) are different for mobile phones ...

Is this math? Or simply phone number literacy?

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