Where I live, telephone numbers have a group of three, called an area code, then another three, called the exchange, and then four.
You say the numbers one at a time, unless they end with 00 or 000.
914-555-7983 is nine one four, five five five, seven nine eight three. You pause where the commas are.
914-555-7900 is nine one four, five five five, seventy-nine hundred.
Some people may say the first one as seventy-nine, eighty-three. I find that harder as the listener than saying them one at a time.
The area code I live in is 610. Some people say "six ten" instead of "six one oh." I also find that harder - I'm used to three digits.